**ByteDance Ltd. **is a Chinese internet technology company headquartered in Beijing and incorporated in the Cayman Islands. It was founded by Zhang Yiming, Liang Rubo and a team of others in 2012, ByteDance developed the video-sharing social networking services and apps TikTok and Chinese-specific counterpart Douyin. ^{}^{}^{}The company is also the developer of the news and information platform Toutiao (“Headlines”). ^{}As of June 2021, ByteDance hosts 1.9 billion monthly active users across all of its content platforms.

It has got a 4.1* rating on Glassdoor and is considered one of the best product-based companies. It is highly regarded for its work-life balance.

They provide good training as well which will be beneficial in future too. You can practice the below ByteDance Interview Questions for the interview. We have collected past frequently asked ByteDance Interview Questions for your reference.

Categories of Questions

## ByteDance Array Questions

**Question 1. Continuous Subarray Sum LeetCode Solution** Problem Statement Continuous Subarray Sum LeetCode Solution – Given an integer array nums and an integer k, return true if nums has a continuous subarray of the size of at least two whose elements sum up to a multiple of k, or false otherwise. An integer x is a multiple of k if there exists an integer n such that x = n * k. 0 is always a ...

**Question 2. Top K Frequent Elements LeetCode Solution** Problem Statement Top K Frequent Elements LeetCode Solution Says that – Given an integer array nums and an integer k, return the k most frequent elements. You may return the answer in any order. Example 1: Input: nums = [1,1,1,2,2,3], k = 2 Output: [1,2] Example 2: Input: nums = [1], k = 1 Output: [1] ...

**Question 3. Minimum Path Sum Leetcode Solution** Problem Statement The Minimum Path Sum LeetCode Solution – “Minimum Path Sum” says that given a n x m grid consisting of non-negative integers and we need to find a path from top-left to bottom right, which minimizes the sum of all numbers along the path. We can only move ...

**Question 4. Insert Delete GetRandom O(1) Leetcode Solution** Problem Statement The Insert Delete GetRandom O(1) LeetCode Solution – “Insert Delete GetRandom O(1)” asks you to implement these four functions in O(1) time complexity. insert(val): Insert the val into the randomized set and return true if the element is initially absent in the set. It returns false when the ...

**Question 5. Daily Temperatures Leetcode Solution** Problem Statement The Daily Temperatures Leetcode Solution: states that given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait after the ith day to get a warmer temperature. If there is no future day for which this is possible, keep answer[i] == 0 instead. ...

**Question 6. Next Permutation Leetcode Solution** Problem Statement The Next Permutation LeetCode Solution – “Next Permutation” states that given an array of integers which is a permutation of first n natural numbers. We need to find the next lexicographically smallest permutation of the given array. The replacement must be in-place and use only constant extra space. ...

**Question 7. Trapping Rain Water Leetcode Solution** Problem Statement The Trapping Rain Water LeetCode Solution – “Trapping Rain Water” states that given an array of heights which represents an elevation map where the width of each bar is 1. We need to find the amount of water trapped after rain. Example: Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: Check ...

**Question 8. Partition to K Equal Sum Subsets Leetcode Solution** Problem Statement The Partition to K Equal Sum Subsets LeetCode Solution – “Partition to K Equal Sum Subsets” states that you’re given the integer array nums and an integer k, return true if it is possible to have k non-empty subsets whose sums are all equal. Example: Input: nums = [4,3,2,3,5,2,1], k = 4 Output: ...

**Question 9. Coin Change 2 Leetcode Solution** Problem Statement The Coin Change 2 LeetCode Solution – “Coin Change 2” states that given an array of distinct integers coins and an integer amount, representing a total amount of money. We need to return the count of the total number of different possible combinations that sum to the amount. ...

**Question 10. Frog Jump Leetcode Solution** Problem Statement The Frog Jump LeetCode Solution – “Frog Jump” states that given the list of stones (positions) sorted in ascending order, determine if the frog can cross the river by landing on the last stone (last index of the array). Initially, the frog is on the first stone and ...

**Question 11. Combination Sum Leetcode Solution** The problem Combination Sum Leetcode Solution provides us an array or list of integers and a target. We are told to find the combinations that can be made using these integers any number of times that add up to the given target. So more formally, we can use the given ...

**Question 12. Maximum Subarray Leetcode Solution** Problem Statement Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Example nums = [-2,1,-3,4,-1,2,1,-5,4] 6 Explanation: [4,-1,2,1] has the largest sum = 6. nums = [-1] -1 Approach 1 (Divide and Conquer) In this approach ...

**Question 13. Unique Paths Leetcode Solution** The problem Unique Paths Leetcode Solution states that you are given two integers representing the size of a grid. Using the size of the grid, the length, and breadth of the grid. We need to find the number of unique paths from the top left corner of the grid to ...

**Question 14. Merge Sorted Arrays Leetcode Solution** In the problem “Merge Sorted Arrays”, we are given two arrays sorted in non-descending order. The first array is not fully filled and has enough space to accommodate all elements of the second array as well. We have to merge the two arrays, such that the first array contains elements ...

**Question 15. Search in Rotated Sorted Array Leetcode Solution** Consider a sorted array but one index was picked and the array was rotated at that point. Now, once the array has been rotated you are required to find a particular target element and return its index. In case, the element is not present, return -1. The problem is generally ...

**Question 16. Kth largest element in an Array Leetcode Solutions** In this problem, we have to return the kth largest element in an unsorted array. Note that the array can have duplicates. So, we have to find the Kth largest element in the sorted order, not the distinct Kth largest element. Example A = {4 , 2 , 5 , 3 ...

**Question 17. Find First and Last Position of Element in Sorted Array Leetcode Solution** Problem statement In this article titled “Find First and Last Position of Element in Sorted Array Leetcode Solution,” we will discuss the solution to a leetcode problem. In the given problem we are given an array. We are also given a target element. Elements in the array are sequenced in ...

**Question 18. Count all subsequences having product less than K** The problem “Count all subsequences having product less than K” states that you are given an array of integers. Now find the number of subsequences that have a product less than a given input K. Example a[] = {1, 2, 3, 4, 5} k = 8 Number of subsequences less ...

**Question 19. Print modified array after executing the commands of addition and subtraction** You are given an array of size n, initially all the values in the array will be 0, and the queries. Each query contains the four values, type of the query T, left point of the range, the right point of a range and a number k, you have to ...

**Question 20. Best Time to Buy and Sell Stock** Problem Statement The problem “Best Time to Buy and Sell Stock” states that you are given an array of prices of length n, where the ith element stores the price of stock on ith day. If we can make only one transaction, that is, to buy on one day and ...

**Question 21. Top K Frequent Elements** Problem Statement In top K frequent elements we have given an array nums[], find the k most frequently occurring elements. Examples nums[] = {1, 1, 1, 2, 2, 3} k = 2 1 2 nums[] = {1} k = 1 1 Naive Approach for Top K Frequent Elements Build ...

**Question 22. Sum of minimum and maximum elements of all subarrays of size k** Problem Statement The problem “Sum of minimum and maximum elements of all subarrays of size k” states that you are given an array containing positive and negative integers, find the sum of minimum and maximum elements of all the sub-arrays of size k. Examples arr[] = {5, 9, 8, 3, ...

**Question 23. Minimum number of distinct elements after removing m items** Problem Statement The problem “Minimum number of distinct elements after removing m items” states that you have an array and an integer m. Each element of the array indicates an item id’s. The problem statement asks to remove m elements in such a way that there should be a minimum ...

**Question 24. Subset Leetcode** In Subset Leetcode problem we have given a set of distinct integers, nums, print all subsets (the power set). Note: The solution set must not contain duplicate subsets. An array A is a subset of an array B if a can be obtained from B by deleting some (possibly, zero ...

**Question 25. Word Search** Word search is something like the word-finding puzzles at some time in our life. Today I bring to the table a modified crossword. My readers must be a bit perplexed as to what I am talking about. Without wasting any more time let us get to the problem statement Can ...

**Question 26. Median of Two Sorted Arrays** Given two sorted arrays A and B of size n and m respectively. Find the median of the final sorted array obtained after merging the given two arrays or in other words, we say that find median of two sorted arrays. ( Expected time complexity: O(log(n)) ) Approach 1 for ...

**Question 27. Search an Element in Sorted Rotated Array** In search in sorted rotated array problem we have given a sorted and rotated array and an element, check if the given element is present in the array or not. Examples Input nums[] = {2, 5, 6, 0, 0, 1, 2} target = 0 Output true Input nums[] = {2, ...

**Question 28. Search in Sorted Rotated Array** An element search in sorted rotated array can be found using binary search in O(logn) time. The objective of this post is to find a given element in a sorted rotated array in O(logn) time. Some example of a sorted rotated array is given. Example Input : arr[] = {7,8,9,10,1,2,3,5,6}; ...

**Question 29. Maximum Subarray** In the Maximum Subarray problem we have given an integer array nums, find the contiguous sub array which has the largest sum and print the maximum sum subarray value. Example Input nums[] = {-2, 1, -3, 4, -1, 2, 1, -5, 4} Output 6 Algorithm The goal is to find ...

**Question 30. Find Peak Element** Let’s understand Find Peak Element problem. Today we have with us an array that needs its peak element. Now, you must be wondering as to what do I mean by the peak element? The peak element is one which is greater than all its neighbours. Example: Given an array of ...

**Question 31. Coin Change Problem** Coin Change Problem – Given some coins of different values c1, c2, … , cs (For instance: 1,4,7….). We need an amount n. Use these given coins to form the amount n. You can use a coin as many times as required. Find the total number of ways in which ...

**Question 32. Maximum Subarray Sum using Divide and Conquer** Problem Statement In the “Maximum Subarray Sum using Divide and Conquer” problem we have given an array of both positive and negative integers. Write a program that will find the largest sum of the contiguous subarray. Input Format The first line containing an integer N. Second-line containing an array of ...

**Question 33. Arrange given Numbers to Form the Biggest Number II** Problem Statement In the “Arrange given Numbers to Form the Biggest Number II” problem, we have given an array of positive integers. Arrange them in such a way that the arrangement will form the largest value. Input Format The first and only one line containing an integer n. Second-line containing ...

**Question 34. Maximum Sum Increasing Subsequence** Problem Statement In the “Maximum Sum Increasing Subsequence” problem we have given an array. Find the sum of the maximum subsequence of the given array, that is the integers in the subsequence are in sorted order. A subsequence is a part of an array which is a sequence that is ...

**Question 35. Find the Peak Element from an Array** Problem Statement In the “Find the Peak Element from an Array” problem we have given an input array of integers. Find a peak element. In an array, an element is a peak element, if the element is greater than both the neighbours. For corner elements, we can consider the only ...

**Question 36. Partition Problem** Problem Statement In the Partition problem, we have given a set that contains n elements. Find whether the given set can be divided into two sets whose sum of elements in the subsets is equal. Example Input arr[] = {4, 5, 11, 9, 8, 3} Output Yes Explanation The array ...

**Question 37. Subarray with Given Sum** Problem Statement In the subarray with the given sum problem, we have given an array containing n positive elements. We have to find the subarray in which the sum of all the elements of the subarray equal to a given_sum. Subarray is obtained from the original array by deleting some ...

**Question 38. Merge Two Sorted Arrays** Problem Statement In merge two sorted arrays problem, we have given two input sorted arrays, we need to merge these two arrays such that the initial numbers after complete sorting should be in the first array and remaining in the second array. Example Input A[] = {1, 3, 5, 7, ...

**Question 39. Count of Triplets With Sum Less than Given Value** Problem Statement We have given an array containing N number of elements. In the given array, Count the number of triplets with a sum less than the given value. Example Input a[] = {1, 2, 3, 4, 5, 6, 7, 8} Sum = 10 Output 7 Possible triplets are : ...

**Question 40. Merging Two Sorted Arrays** Problem Statement In merging two sorted arrays problem we have given two sorted arrays, one array with size m+n and the other array with size n. We will merge the n sized array into m+n sized array and print the m+n sized merged array. Example Input 6 3 M[] = ...

**Question 41. Find Triplet in Array With a Given Sum** Problem Statement Given an array of integers, find the combination of three elements in the array whose sum is equal to a given value X. Here we will print the first combination that we get. If there is no such combination then print -1. Example Input N=5, X=15 arr[] = ...

**Question 42. Smallest Positive Number Missing in an Unsorted Array** Problem Statement In the given unsorted array find the smallest positive number missing in an unsorted array. A positive integer doesn’t include 0. We can modify the original array if needed. The array may contain positive and negative numbers. Example a. Input array : [3, 4, -1, 0, -2, 2, 1, ...

**Question 43. Move All the Zeros to the End of the Given Array** Problem Statement In the given array move all the zeros which are present in the array to the end of the array. Here there is always a way exist to insert all the number of zeroes to the end of the array. Example Input 9 9 17 0 14 0 ...

**Question 44. Count Number of Occurrences in a Sorted Array** Problem Statement In the “Count Number of Occurrences in a Sorted Array” problem, we have given a sorted array. Count the number of occurrences or frequency in a sorted array of X where X is an integer. Example Input 13 1 2 2 2 2 3 3 3 4 4 ...

**Question 45. A Product Array Puzzle** Problem Statement In a product array puzzle problem we need to construct an array where the ith element will be the product of all the elements in the given array except element at the ith position. Example Input 5 10 3 5 6 2 Output 180 600 360 300 900 ...

**Question 46. Majority Element** Problem Statement Given a sorted array, we need to find the majority element from the sorted array. Majority element: Number occurring more than half the size of the array. Here we have given a number x we have to check it is the majority_element or not. Example Input 5 2 ...

## ByteDance String Questions

**Question 47. Score of Parenthesis LeetCode Solution** Problem Statement The score of Parenthesis LeetCode Solution says – Given a balanced parentheses string s and return the maximum score. The score of a balanced parenthesis string is based on the following rules: "()" has score 1. AB has score A + B, where A and B are balanced parenthesis strings. (A) has score 2 * A, where A is a ...

**Question 48. Design Add and Search Words Data Structure LeetCode Solution** Problem Statement: Design Add and Search Words Data Structure LeetCode Solution says – Design a data structure that supports adding new words and finding if a string matches any previously added string. Implement the WordDictionary class: WordDictionary() Initializes the object. void addWord(word) Adds word to the data structure, it can be matched later. bool search(word) Returns true if there ...

**Question 49. Decode String Leetcode Solution** Problem Statement The Decode String LeetCode Solution – “Decode String” asks you to convert the encoded string into a decoded string. The encoding rule is k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times where k is a positive integer. Example: Input: s = "3[a]2[bc]" Output: "aaabcbc" ...

**Question 50. Different Ways to Add Parentheses Leetcode Solution** Problem Statement The Different Ways to Add Parentheses LeetCode Solution – “Different Ways to Add Parentheses” states that given a string expression of numbers and operators. We need to return all possible results from computing all different possible ways to group numbers and operators. Return the answer in any order. ...

**Question 51. Generate Parentheses Leetcode Solution** Problem Statement The Generate Parentheses LeetCode Solution – “Generate Parentheses” states that given the value of n. We need to generate all combinations of n pairs of parentheses. Return the answer in the form of a vector of strings of well-formed parentheses. Example: Input: n = 3 Output: ["((()))","(()())","(())()","()(())","()()()"] Explanation: ...

**Question 52. Largest Number Leetcode Solution** Problem Statement The Largest Number LeetCode Solution – “Largest Number” states that given a list of non-negative integers nums, we need to arrange the numbers in such a way that they form the largest number and return it. Since the result may be very large, so you need to return ...

**Question 53. Implement Trie (Prefix Tree) Leetcode Solution** Problem Statement The Implement Trie (Prefix Tree) LeetCode Solution – “Implement Trie (Prefix Tree)” asks you to implement the Trie Data Structure that performs inserting, searching and prefix searching efficiently. Example: Input: ["Trie", "insert", "search", "search", "startsWith", "insert", "search"] [[], ["apple"], ["apple"], ["app"], ["app"], ["app"], ["app"]] Output: [null, null, true, false, true, null, true] Explanation: After inserting all the strings, trie looks like this. Word apple is searched which ...

**Question 54. Remove Invalid Parentheses Leetcode Solution** Problem Statement The Remove Invalid Parentheses Leetcode Solution – states that you’re given a string s that contains parenthesis and lowercase letters. We need to remove the minimum number of invalid parentheses to make the input string valid. We need to return all possible results in any order. A string is ...

**Question 55. Multiply Strings Leetcode Solution** The problem Multiply Strings Leetcode solution asks us to multiply two strings which are given to us as input. We are required to print or return this result of multiplying to the caller function. So to put it more formally given two strings, find the product of the given strings. ...

**Question 56. Longest Repeated Subsequence** The problem “Longest Repeated Subsequence” states that you are given a string as an input. Find out the longest repeated subsequence, that is the subsequence that exists twice in the string. Example aeafbdfdg 3 (afd) Approach The problem asks us to find out the longest repeated subsequence in the string. ...

**Question 57. Longest Substring Without Repeating Characters LeetCode Solution** Longest Substring Without Repeating Characters LeetCode Solution – Given a string, we have to find the length of the longest substring without repeating characters. Let’s look into a few examples: Example pwwkew 3 Explanation: Answer is “wke” with length 3 aav 2 Explanation: Answer is “av” with length 2 Approach-1 ...

**Question 58. Palindrome Substring Queries** Problem Statement The problem “Palindrome Substring Queries” states that you are given a String and some queries. With those queries, you have to determine if the formed substring from that query is a palindrome or not. Example String str = "aaabbabbaaa" Queries q[] = { {2, 3}, {2, 8},{5, 7}, ...

**Question 59. Maximum weight transformation of a given string** Problem Statement The maximum weight transformation of a given string problem states that given a string consisting only of two characters ‘A’ and ‘B’. We have an operation where we can transform string to another string by toggling any character. Thus many transformations are possible. Out of all the possible ...

**Question 60. Edit Distance** In the edit distance problem we have to find the minimum number of operations required to convert a string X of length n to another string Y of length m. Operations allowed: Insertion Deletion Substitution Example Input: String1 = “abcd” String2 = “abe” Output: Minimum operations required is 2 ( ...

**Question 61. Decode String** Suppose, you are given an encoded string. A string is encoded in some kind of pattern, your task is to decode the string. Let us say, < no of times string occurs > [string ] Example Input 3[b]2[bc] Output bbbcaca Explanation Here “b” occurs 3times and “ca” occur 2 times. ...

**Question 62. Next Permutation** In the next permutation problem we have given a word, find the lexicographically greater_permutation of it. Example input : str = "tutorialcup" output : tutorialpcu input : str = "nmhdgfecba" output : nmheabcdfg input : str = "algorithms" output : algorithsm input : str = "spoonfeed" output : Next Permutation ...

**Question 63. Valid Parentheses LeetCode Solution** In Valid Parentheses LeetCode problem we have given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid. Here we will provide a Valid Parentheses LeetCode Solution to you. An input string is valid if: Open brackets must be closed ...

**Question 64. Permutations of a Given String Using STL** Problem Statement In the “Permutations of a Given String Using STL” problem, we have given a string “s”. Print all the permutations of the input string using STL functions. Input Format The first and only one line containing a string “s”. Output Format Print all the permutation of the given ...

**Question 65. Length of Longest valid Substring** Problem Statement In the “Length of Longest valid Substring” we have given a string that contains the opening and closing parenthesis only. Write a program that will find the longest valid parenthesis substring. Input Format The first and only one line containing a string s. Output Format The first and ...

**Question 66. Smallest window in a string containing all characters of another string** Find the shortest substring in a given string that contains all the characters of a given word or Find the Smallest window in a string containing all characters of another string Given two strings s and t, write a function that will find the minimum window in s which will ...

**Question 67. Arrange given Numbers to Form the Biggest Number II** Problem Statement In the “Arrange given Numbers to Form the Biggest Number II” problem, we have given an array of positive integers. Arrange them in such a way that the arrangement will form the largest value. Input Format The first and only one line containing an integer n. Second-line containing ...

## ByteDance Tree Questions

**Question 68. Vertical Order Traversal of Binary Tree LeetCode Solution** Problem Statement Vertical Order Traversal of Binary Tree LeetCode Solution says – Given the root of a binary tree, calculate the vertical order traversal of the binary tree. For each node at position (row, col), its left and right children will be at positions (row + 1, col - 1) and (row + 1, col + 1) respectively. ...

**Question 69. Flatten Binary Tree to Linked List LeetCode Solution** Flatten Binary Tree to Linked List LeetCode Solution says that – Given the root of a binary tree, flatten the tree into a “linked list”: The “linked list” should use the same TreeNode class where the right child pointer points to the next node in the list and the left child pointer is always null. The “linked list” ...

**Question 70. Lowest Common Ancestor of a Binary Tree Leetcode Solution** Problem Statement The Lowest Common Ancestor of a Binary Tree LeetCode Solution – “Lowest Common Ancestor of a Binary Tree” states that given the root of the binary tree and two nodes of the tree. We need to find the lowest common ancestor of these two nodes. The Lowest Common ...

**Question 71. Delete Nodes and Return Forest Leetcode Solution** Problem Statement The Delete Nodes and Return Forest LeetCode Solution – “Delete Nodes and Return Forest” states that given the root of the binary tree where each node has a distinct value. We’re also given an array, to_delete, where we need to delete all the nodes with values contained in ...

**Question 72. Recover Binary Search Tree Leetcode Solution** Problem Statement The Recover Binary Search Tree LeetCode Solution – “Recover Binary Search Tree” states that given the root of the binary search tree, where the values of exactly two nodes are swapped by mistake. We need to recover the tree without changing its structure. Example: Input: root = [1,3,null,null,2] Output: [3,1,null,null,2] ...

**Question 73. Minimum number of distinct elements after removing m items** Problem Statement The problem “Minimum number of distinct elements after removing m items” states that you have an array and an integer m. Each element of the array indicates an item id’s. The problem statement asks to remove m elements in such a way that there should be a minimum ...

**Question 74. Convert BST to Min Heap** Problem Statement Given a complete Binary Search Tree, write an algorithm to convert it into a Min Heap, which is to convert BST to Min Heap. The Min Heap should be such that the values on the left of a node must be less than the values on the right ...

**Question 75. Convert a normal BST to Balanced BST** Problem Statement Given a Binary Search Tree(BST), write an algorithm to convert the BST to a Balanced Binary Search Tree. A balanced Binary Search tree is nothing but a binary search tree whose difference between the height of left subtree and right subtree is less than or equal to 1. ...

**Question 76. Construct Binary Tree from Given Inorder and Preorder Traversals** In this problem, we have inorder and preorder of the binary tree. We need to construct a binary tree from the given Inorder and Preorder traversals. Example Input: Inorder= [D, B, E, A, F, C] Preorder= [A, B, D, E, C, F] Output: Pre-order traversal of the tree formed by ...

**Question 77. Recover Binary Search Tree** Consider a binary search tree, two nodes of the tree have been swapped, design an algorithm to recover the binary search Tree. Example Consider the binary search tree given below whose two nodes have been swapped as input. Incorrect nodes on the BST are detected(highlighted) and then swapped to obtain ...

**Question 78. Validate Binary Search Tree** Problem In Validate Binary Search Tree problem we have given the root of a tree, we have to check if it is a binary search tree or not. Example : Output: true Explanation: The given tree is a binary search tree because all elements which are left to each subtree ...

## ByteDance Graph Questions

**Question 79. Is Graph Bipartite? LeetCode Solution** Problem Statement Is Graph Bipartite LeetCode Solution- There is an undirected graph with n nodes, where each node is numbered between 0 and n - 1. You are given a 2D array graph, where graph[u] is an array of nodes that node u is adjacent to. More formally, for each v in graph[u], there is an undirected edge between node u and node v. The graph has ...

## ByteDance Stack Questions

**Question 80. Score of Parenthesis LeetCode Solution** Problem Statement The score of Parenthesis LeetCode Solution says – Given a balanced parentheses string s and return the maximum score. The score of a balanced parenthesis string is based on the following rules: "()" has score 1. AB has score A + B, where A and B are balanced parenthesis strings. (A) has score 2 * A, where A is a ...

**Question 81. Decode String Leetcode Solution** Problem Statement The Decode String LeetCode Solution – “Decode String” asks you to convert the encoded string into a decoded string. The encoding rule is k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times where k is a positive integer. Example: Input: s = "3[a]2[bc]" Output: "aaabcbc" ...

**Question 82. Flatten Binary Tree to Linked List LeetCode Solution** Flatten Binary Tree to Linked List LeetCode Solution says that – Given the root of a binary tree, flatten the tree into a “linked list”: The “linked list” should use the same TreeNode class where the right child pointer points to the next node in the list and the left child pointer is always null. The “linked list” ...

**Question 83. Add Two Numbers II Leetcode Solution** Problem Statement The Add Two Numbers II LeetCode Solution – “Add Two Numbers II” states that two non-empty linked lists represent two non-negative integers where the most significant digit comes first and each node contains exactly one digit. We need to add the two numbers and return the sum as ...

**Question 84. Daily Temperatures Leetcode Solution** Problem Statement The Daily Temperatures Leetcode Solution: states that given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait after the ith day to get a warmer temperature. If there is no future day for which this is possible, keep answer[i] == 0 instead. ...

**Question 85. Trapping Rain Water Leetcode Solution** Problem Statement The Trapping Rain Water LeetCode Solution – “Trapping Rain Water” states that given an array of heights which represents an elevation map where the width of each bar is 1. We need to find the amount of water trapped after rain. Example: Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: Check ...

**Question 86. Decode String** Suppose, you are given an encoded string. A string is encoded in some kind of pattern, your task is to decode the string. Let us say, < no of times string occurs > [string ] Example Input 3[b]2[bc] Output bbbcaca Explanation Here “b” occurs 3times and “ca” occur 2 times. ...

## ByteDance Queue Questions

**Question 87. Sum of minimum and maximum elements of all subarrays of size k** Problem Statement The problem “Sum of minimum and maximum elements of all subarrays of size k” states that you are given an array containing positive and negative integers, find the sum of minimum and maximum elements of all the sub-arrays of size k. Examples arr[] = {5, 9, 8, 3, ...

**Question 88. Queue Reconstruction by Height** Problem Description of Queue Reconstruction by Height Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers (h, k), where h is the height of the person and k is the number of people in front of this person ...

## ByteDance Matrix Questions

**Question 89. Minimum Path Sum Leetcode Solution** Problem Statement The Minimum Path Sum LeetCode Solution – “Minimum Path Sum” says that given a n x m grid consisting of non-negative integers and we need to find a path from top-left to bottom right, which minimizes the sum of all numbers along the path. We can only move ...

**Question 90. Word Search Leetcode Solution** Problem Statement Given an m x n board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cells, where “adjacent” cells are horizontally or vertically neighbouring. The same letter cell may not be used more than once. Example ...

## ByteDance Other Questions

**Question 91. Invert Binary Tree LeetCode Solution** Problem Statement: Invert Binary Tree LeetCode Solution : Given the root of a binary tree, invert the tree, and return its root. An inverted form of a Binary Tree is another Binary Tree with left and right children of all non-leaf nodes interchanged. You may also call it the mirror of the input tree. ...

**Question 92. Implement Rand10() Using Rand7() Leetcode Solution** Problem Statement: Implement Rand10() Using Rand7() Leetcode Solution – Given the API rand7() that generates a uniform random integer in the range [1, 7], write a function rand10() that produces a uniform random integer in the range [1, 10]. You can only call the API rand7(), and you shouldn’t call any other ...

**Question 93. Reverse Nodes in k-Group LeetCode Solution** Problem Statement: Reverse Nodes in k-Group LeetCode Solution – Given the head of a linked list, reverse the nodes of the list k at a time, and return the modified list. k is a positive integer and is less than or equal to the length of the linked list. If the number of nodes is ...

**Question 94. Find First and Last Position of Element in Sorted Array LeetCode Solution** Problem Statement: Find First and Last Position of Element in Sorted Array LeetCode Solution says that – given an array of integers nums sorted in non-decreasing order, find the starting and ending position of a given target value. If target is not found in the array, return [-1, -1]. You must write an algorithm with O(log n) runtime complexity. ...

**Question 95. The Number of Weak Characters in the Game LeetCode Solution** Problem Statement: The Number of Weak Characters in the Game LeetCode Solution : You are playing a game that contains multiple characters, and each of the characters has two main properties: attack and defense. You are given a 2D integer array properties where properties[i] = [attacki, defensei] represents the properties of the ith character in the game. A character is said ...

**Question 96. Find Peak Element LeetCode Solution** Problem Statement Find Peak Element LeetCode Solution says that – A peak element is an element that is strictly greater than its neighbors. Given a 0-indexed integer array nums, find a peak element, and return its index. If the array contains multiple peaks, return the index to any of the peaks. You may imagine ...

**Question 97. Group Anagrams LeetCode Solution** Problem Statement Group Anagrams LeetCode Solution Says that – Given an array of strings strs, group the anagrams together. You can return the answer in any order. An Anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once. Example 1: ...

**Question 98. Sliding Window Maximum LeetCode Solution** Problem Statement Sliding Window Maximum LeetCode Solution Says that – You are given an array of integers nums, and there is a sliding window of size k which is moving from the very left of the array to the very right. You can only see the k numbers in the window. Each time ...

**Question 99. Container With Most Water LeetCode Solution** Problem Statement Container With Most Water LeetCode Solution says that – You are given an integer array height of length n. There are n vertical lines are drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). Find two lines that together with the x-axis form a container, such that the container ...

**Question 100. Next Permutation LeetCode Solution** Problem Statement Next Permutation LeetCode Solution – A permutation of an array of integers is an arrangement of its members into a sequence or linear order. For example, for arr = [1,2,3], the following are considered permutations of arr: [1,2,3], [1,3,2], [3,1,2], [2,3,1]. The next permutation of an array of integers is the next lexicographically greater permutation of ...

**Question 101. Flatten Binary Tree to Linked List LeetCode Solution** Problem Statement: Flatten Binary Tree to Linked List LeetCode Solution: Given the root of a binary tree, flatten the tree into a “linked list”: The “linked list” should use the same TreeNode class where the right child pointer points to the next node in the list and the left child pointer is always null. The “linked list” should be ...

**Question 102. Valid Triangle Number LeetCode Solution** Problem Statement Valid Triangle Number LeetCode Solution – Given an integer array nums, return the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle. Input: nums = [2,2,3,4] Output: 3 Explanation: Valid combinations are: 2,3,4 (using the first 2) ...

**Question 103. Unique Binary Search Trees LeetCode Solution** Unique Binary Search Trees LeetCode Solution says that – Given an integer n, return the number of structurally unique BST’s (binary search trees) which has exactly n nodes of unique values from 1 to n. Example 1: Input: n = 3 Output: 5 Example 2: Input: n = 1 Output: 1 Constraints: 1 <= n <= 19 ...

**Question 104. Range Sum of BST LeetCode Solution** Range Sum of BST LeetCode Solution says that – Given the root the node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high]. Example 1: Input: root = [10,5,15,3,7,null,18], low = 7, high = 15 Output: 32 Explanation: ...

**Question 105. Reverse Integer Leetcode Solution** Problem Statement Reverse Integer LeetCode Solution says that – Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0. Assume the environment does not allow you to store 64-bit integers (signed or unsigned). Example 1: ...

**Question 106. Find K Closest Elements LeetCode Solution** Problem Statement Find K Closest Elements LeetCode Solution – Given a sorted integer array arr, two integers k and x, return the k closest integers to x in the array. The result should also be sorted in ascending order. An integer a is closer to x than an integer b if: |a - x| < |b - x|, or |a - x| == |b - ...

**Question 107. Valid Triangle Number LeetCode Solution** Problem Statement: Valid Triangle Number LeetCode Solution says – Given an integer array nums, return the number of triplets chosen from the array that can make triangles if we take them as side lengths of a triangle. Example 1: Input: nums = [2,2,3,4] Output: 3 Explanation: Valid combinations are: 2,3,4 (using ...

**Question 108. Odd Even Linked List Leetcode Solution** Problem Statement The Odd-Even Linked List LeetCode Solution – “Odd-Even Linked List” states that given a non-empty singly linked list. We need to group all nodes with odd indices together followed by the nodes with even indices, and return the reordered list. Note that the relative order inside both the ...

**Question 109. Robot Room Cleaner Leetcode Solution** Problem Statement The Robot Room Cleaner LeetCode Solution – “Robot Room Cleaner” states that given the robot in a m x n a binary grid where 0 represents a wall and 1 represents an empty slot. The initial position of the robot is guaranteed to be empty and the robot moves inside the ...

**Question 110. LRU Cache Leetcode Solution** Problem Statement The LRU Cache LeetCode Solution – “LRU Cache” asks you to design a data structure that follows Least Recently Used (LRU) Cache We need to implement LRUCache class that has the following functions: LRUCache(int capacity): Initializes the LRU cache with positive size capacity. int get(int key): Return the value ...

**Question 111. Merge k Sorted Lists Leetcode Solution** Problem Statement The Merge k Sorted Lists LeetCode Solution – “Merge k Sorted Lists” states that given the array of k linked lists, where each linked list has its values sorted in ascending order. We need to merge all the k-linked lists into one single linked list and return the ...

**Question 112. Remove Duplicates from Sorted List LeetCode Solution** Problem Statement Remove Duplicates from Sorted List LeetCode Solution – We are given the head of a sorted linked list. We are asked to delete all the duplicates such that each element appears only once and return the linked list sorted as well. Examples & Explanations Example 1: Input: head ...

**Question 113. Clone Graph LeetCode Solution** Problem Statement Clone Graph LeetCode Solution – We are given a reference of a node in a connected undirected graph and are asked to return a deep copy of the graph. A deep copy is basically a clone where no node present in the deep copy should have the reference ...

**Question 114. Kth Smallest Element in a Sorted Matrix LeetCode Solution** Problem Statement Kth Smallest Element in a Sorted Matrix LeetCode Solution – We are given a matrix of size n where each of the rows and columns is sorted in ascending order. We are asked to return the kth smallest element in the matrix. Note that it is the kth ...

**Question 115. Number of Dice Rolls With Target Sum LeetCode Solution** Problem Statement Number of Dice Rolls With Target Sum LeetCode Solution – You have n dice and each die has k faces numbered from 1 to k. Given three integers n, k, and target, return the number of possible ways (out of the kn total ways) to roll the dice so the sum of the face-up numbers equals target. Since the answer may be ...

**Question 116. Remove Duplicates from Sorted List II LeetCode Solution** Problem Statement Remove Duplicates from Sorted List II LeetCode Solution – Given the head of a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. Return the linked list sorted as well. Input: head = [1,2,3,3,4,4,5] Output: [1,2,5] Explanation The idea here is to traverse ...

**Question 117. Shortest Path in a Grid with Obstacles Elimination LeetCode Solution** Problem Statement Shortest Path in a Grid with Obstacles Elimination LeetCode Solution – You are given an m x n integer matrix grid where each cell is either 0 (empty) or 1 (obstacle). You can move up, down, left, or right from and to an empty cell in one step. Return the minimum number of steps to walk from the upper left ...

**Question 118. Invert Binary Tree LeetCode Solution** Problem Statement: Invert Binary Tree LeetCode Solution – In this question, Given a root of any binary tree, the solution is required to invert the binary tree meaning the left tree should become the right tree and vice versa. Explanation We can ask ourselves which tree traversal would be ...

**Question 119. N-Queens LeetCode Solution** Problem Statement N-Queens LeetCode Solution – The n-queens puzzle is the problem of placing n queens on a n x n chessboard such that no two queens attack each other. Given an integer n, return all distinct solutions to the n-queens puzzle. You may return the answer in any order. Each solution contains a distinct board configuration of the ...

**Question 120. Largest Rectangle in Histogram LeetCode Solution** Problem Statement Largest Rectangle in Histogram LeetCode Solution – Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram. Example Test Case 1: Input: heights = [2, 1, 5, 6, 2, 3] Output: 10 Explanation: ...

**Question 121. Binary Tree Right Side View LeetCode Solution** Problem Statement Binary Tree Right Side View LeetCode Solution – Given the root of a binary tree, imagine yourself standing on the right side of it, and return the values of the nodes you can see ordered from top to bottom. Example Test Case 1: Input: root = [1, 2, 3, null, 5, null, ...

**Question 122. Time Based Key-Value Store LeetCode Solution** Problem Statement Time Based Key-Value Store LeetCode Solution – Design a time-based key-value data structure that can store multiple values for the same key at different time stamps and retrieve the key’s value at a certain timestamp. Implement the TimeMap class: TimeMap() Initializes the object of the data structure. void set(String key, String ...

**Question 123. Find Median from Data Stream LeetCode Solution** Problem Statement Find Median from Data Stream LeetCode Solution – The median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value and the median is the mean of the two middle values. For example, for arr = [2,3,4], the median ...

**Question 124. Permutation in String Leetcode Solution** Problem Statement : Permutation in String Leetcode Solution – Given two strings s1 and s2, return true if s2 contains a permutation of s1, or false otherwise. In other words, return true if one of s1‘s permutations is the substring of s2. Example : Example 1 Input: s1 = "ab", s2 = "eidbaooo" Output: true Explanation: s2 contains one permutation of s1 ("ba"). ...

**Question 125. Asteroid Collision LeetCode Solution** Problem Statement Asteroid Collision LeetCode Solution – We are given an array asteroids of integers representing asteroids in a row. For each asteroid, the absolute value represents its size, and the sign represents its direction (positive meaning right, negative meaning left). Each asteroid moves at the same speed. Find out the state ...

**Question 126. Longest Increasing Path in a Matrix LeetCode Solution** Problem Statement Longest Increasing Path in a Matrix LeetCode Solution – Given an m x n integers matrix, return the length of the longest increasing path in matrix. From each cell, you can either move in four directions: left, right, up, or down. You may not move diagonally or move outside the boundary (i.e., wrap-around is not allowed). Input: ...

**Question 127. Optimal Account Balancing LeetCode Solution** Problem Statement Optimal Account Balancing LeetCode Solution – You are given an array of transactions transactions where transactions[i] = [fromi, toi, amounti] indicates that the person with ID = fromi gave amounti $ to the person with ID = toi. Return the minimum number of transactions required to settle the debt. Input: transactions = [[0,1,10],[2,0,5]] Output: 2 Explanation: Person #0 ...

**Question 128. Serialize and Deserialize Binary Tree LeetCode Solution** Problem Statement Serialize and Deserialize Binary Tree LeetCode Solution – Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in ...

**Question 129. Binary Tree Maximum Path Sum LeetCode Solution** Problem Statement Binary Tree Maximum Path Sum LeetCode Solution – A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence at most once. Note that the path does not need ...

**Question 130. Minimum Knight Moves LeetCode Solution** Problem Statement Minimum Knight Moves LeetCode Solution – In an infinite chessboard with coordinates from -infinity to +infinity, you have a knight at square [0, 0]. A knight has 8 possible moves it can make, as illustrated below. Each move is two squares in a cardinal direction, then one square in an orthogonal direction. Return the minimum number ...

**Question 131. Binary Tree Zigzag Level Order Traversal LeetCode Solution** Problem Statement Binary Tree Zigzag Level Order Traversal LeetCode Solution – Given the root of a binary tree, return the zigzag level order traversal of its nodes’ values. (i.e., from left to right, then right to left for the next level and alternate between). Input: root = [3,9,20,null,null,15,7] Output: [[3],[20,9],[15,7]] Explanation We ...

**Question 132. Missing Element in Sorted Array LeetCode Solution** Problem Statement: Missing Element in Sorted Array LeetCode Solution – Given an integer array nums which are sorted in ascending order and all of its elements are unique and given also an integer k, return the kth missing number starting from the leftmost number of the array. Example: Example 1 Input: nums = [4,7,9,10], k = ...

**Question 133. Alien Dictionary LeetCode Solution** Problem Statement Alien Dictionary LeetCode Solution – There is a new alien language that uses the English alphabet. However, the order among the letters is unknown to you. You are given a list of strings words from the alien language’s dictionary, where the strings in words are sorted lexicographically by the rules of this new language. ...

**Question 134. Intersection of Two Linked Lists LeetCode Solution** Problem Statement Intersection of Two Linked Lists LeetCode Solution – We are given the heads of two strongly linked-lists headA and headB. It is also given that the two linked lists may intersect at some point. We are asked to return the node at which they intersect or null if ...

**Question 135. Permutation Sequence LeetCode Solution** Problem Statement Permutation Sequence LeetCode Solution – The set [1, 2, 3, ..., n] contains a total of n! unique permutations. By listing and labeling all of the permutations in order, we get the following sequence for n = 3: "123" "132" "213" "231" "312" "321" Given n and k, return the kth permutation sequence. Example Test Case 1: Input: n ...

**Question 136. Rotate Image LeetCode Solution** Problem Statement Rotate Image LeetCode Solution – You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise). You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate another 2D matrix and do the rotation. Example Test Case 1: Input: ...

**Question 137. Top K Frequent Words LeetCode Solution** Problem Statement Top K Frequent Words LeetCode Solution – Given an array of strings words and an integer k, return the k most frequent strings. Return the answer sorted by the frequency from highest to lowest. Sort the words with the same frequency by their lexicographical order. Example Test Case 1: Input: words = [“i”,”love”,”leetcode”,”i”,”love”,”coding”] k = 2 Output: [“i”,”love”] Explanation ...

**Question 138. Merge Sorted Array LeetCode Solution** Problem Statement Merge Sorted Array LeetCode Solution – You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively. Merge nums1 and nums2 into a single array sorted in non-decreasing order. The final sorted array should not be returned by the function, but instead be stored inside the array nums1. ...

**Question 139. Employee Free Time LeetCode Solution** Problem Statement Employee Free Time LeetCode Solution – We are given a list schedule of employees, which represents the working time for each employee. Each employee has a list of non-overlapping Intervals, and these intervals are in sorted order. Return the list of finite intervals representing the common, positive-length free time for all employees, also in ...

**Question 140. Number of Distinct Islands Leetcode Solution** Problem Statement The Number of Distinct Islands LeetCode Solution – “Number of Distinct Islands” states that given a n x m binary matrix. An island is a group of 1‘s (representing land) connected 4-directionally (horizontal or vertical). An island is considered to be the same as another if and only if one island ...

**Question 141. Restore IP Addresses Leetcode Solution** Problem Statement The Restore IP Addresses LeetCode Solution – “Restore IP Addresses” states that given the string which contains only digits, we need to return all possible valid IP Addresses in any order that can be formed by inserting dots into the string. Note that we’re not allowed to return ...

**Question 142. String Compression LeetCode Solution** Problem Statement String Compression LeetCode Solution – Given an array of characters chars, compress it using the following algorithm: Begin with an empty string s. For each group of consecutive repeating characters in chars: If the group’s length is 1, append the character to s. Otherwise, append the character followed by the group’s length. The compressed string ...

**Question 143. Possible Bipartition LeetCode Solution** Problem Statement Possible Bipartition LeetCode Solution – We want to split a group of n people (labeled from 1 to n) into two groups of any size. Each person may dislike some other people, and they should not go into the same group. Given the integer n and the array dislikes where dislikes[i] = [ai, bi] indicates that the person labeled ai does ...

**Question 144. Maximum Product of Splitted Binary Tree LeetCode Solution** Problem Statement Maximum Product of Splitted Binary Tree LeetCode Solution – Given the root of a binary tree, split the binary tree into two subtrees by removing one edge such that the product of the sums of the subtrees is maximized. Return the maximum product of the sums of the two subtrees. ...

**Question 145. Maximum Product of Three Numbers LeetCode Solution** Problem Statement Maximum Product of Three Numbers LeetCode Solution – We are given an array, the question asks us to calculate the maximum product of any 3 numbers. Examples Example 1: Input: nums = [1,2,3] Output: 6 Example 2: Input: nums = [1,2,3,4] Output: 24 Example 3: Input: nums = ...

**Question 146. Random Pick Index LeetCode Solution** Problem Statement Random Pick Index LeetCode Solution- We are given a constructor of class “Solution” and a function “pick” of type int. We are required to implement the “Solution” class as Solution(int[] nums) Initializes the object with the array nums. int pick(int target) Picks a random index i from nums where nums[i] == target. If there are multiple ...

**Question 147. Next Greater Element III LeetCode Solution** Problem Statement The problem, Next Greater Element III LeetCode Solution states that you are given a positive integer n and you need to find the next greatest integer using the digits present in n only. If there does not exist any such integer, you need to print -1. Moreover, the new ...

**Question 148. Binary Tree Longest Consecutive Sequence LeetCode Solution** Problem Statement Binary Tree Longest Consecutive Sequence LeetCode Solution – Given the root of a binary tree, return the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along with the parent-child connections. The longest consecutive ...

**Question 149. Move Zeroes LeetCode Solution** Problem Statement The problem, Move Zeroes LeetCode Solution states that you are given an array containing zero and non-zero elements and you need to move all the zeroes to the end of the array, maintaining the relative order of non-zero elements in the array. You also need to implement an in-place ...

**Question 150. 01 Matrix LeetCode Solution** Problem Statement In this problem 01 Matrix LeetCode Solution, we need to find the distance of the nearest 0 for each cell of the given matrix. The matrix consists only of 0’s and 1’s and the distance of any two adjacent cells is 1. Examples Example 1: Input: mat = ...

**Question 151. Factorial Trailing Zeroes LeetCode Solution** Problem Statement Factorial Trailing Zeroes LeetCode Solution – Given an integer n, return the number of trailing zeroes in n!. Note that n! = n * (n - 1) * (n - 2) * ... * 3 * 2 * 1. Input: n = 3 Output: 0 Explanation: 3! = 6, no trailing ...

**Question 152. Word Ladder LeetCode Solution** Problem Statement The Word Ladder LeetCode Solution – “Word Ladder” states that you are given a string beginWord, string endWord, and a wordList. We need to find the shortest transformation sequence length (if no path exists, print 0) from beginWord to endWord following the given conditions: All the Intermediate Words should ...

**Question 153. Longest Substring with At Least K Repeating Characters LeetCode Solution** Problem Statement The problem Longest Substring with At Least K Repeating Characters LeetCode Solution says given a string S and an integer k, return the length of the longest substring of S such that the frequency of each character in this substring is greater than or equal to k. Example for Longest Substring with At Least ...

**Question 154. Last Stone Weight II LeetCode Solution** Problem Statement The problem Last Stone Weight II says you are given an array of integers stones where stones[i] is the weight of the ith stone. We are playing a game with the stones. On each turn, we choose any two stones and smash them together. Suppose the stones have weights x and y ...

**Question 155. Largest BST Subtree LeetCode Solution** Problem Statement The Largest BST Subtree LeetCode Solution problem says given the root of a binary tree, find the largest subtree, which is also a Binary Search Tree (BST), where the largest means subtree having the largest number of nodes. Note: A subtree must include all of its descendants. In a Binary ...

**Question 156. Meeting Rooms II LeetCode Solution** Problem Statement The Meeting Rooms II LeetCode Solution – “Meeting Rooms II” states that you are given an array of meeting time intervals “intervals” where “intervals[i] = [ start[i], end[i] ]”, return the minimum number of conference rooms required. Example: intervals = [[0,30],[5,10],[15,20]] 2 Explanation: Meeting one can be done ...

**Question 157. Subarray Sum Equals K LeetCode Solution** Problem Statement The Subarray Sum Equals K LeetCode Solution – “Subarray Sum Equals K” states that you are given an array of integers “nums” and an integer ‘k’, return the total number of continuous subarrays whose sum equals to ‘k’. Example: nums = [1, 2, 3], k=3 2 Explanation: There ...

**Question 158. Longest Palindromic Substring LeetCode Solution** Problem Statement The Longest Palindromic Substring LeetCode Solution – “Longest Palindromic Substring” states that You are Given a string s, return the longest palindromic substring in s. Note: A palindrome is a word that reads the same backward as forwards, e.g. madam. Example: s = "babad" "bab" Explanation: All ...

**Question 159. Best Time to Buy and Sell Stock LeetCode Solution** Problem Statement The Best Time to Buy and Sell Stock LeetCode Solution – “Best Time to Buy and Sell Stock” states that You are given an array of prices where prices[i] is the price of a given stock on an ith day. You want to maximize your profit by choosing ...

**Question 160. LRU Cache LeetCode Solution** Question Design a data structure that follows the constraints of a Least Recently Used (LRU) cache. Implement the LRUCache class: LRUCache(int capacity) Initialize the LRU cache with positive size capacity. int get(int key) Return the value of the key if the key exists, otherwise return -1. void put(int key, int value) Update the value of the key if the key exists. Otherwise, add the key-value pair to ...

**Question 161. Permutations Leetcode Solution** The problem Permutations Leetcode Solution provides a simple sequence of integers and asks us to return a complete vector or array of all the permutations of the given sequence. So, before going into solving the problem. We should be familiar with permutations. So, a permutation is nothing but an arrangement ...

**Question 162. Two Sum Leetcode Solution** In this problem, we have to find a pair of two distinct indices in a sorted array that their values add up to a given target. We can assume that the array has only one pair of integers that add up to the target sum. Note that the array is ...

**Question 163. Lexicographical Numbers Leetcode Solution** Problem statement In the problem ” Lexicographical Numbers” we are given a number n. Our task is to print numbers between 1 and n in lexicographical order. Example n=13 [1 10 11 12 13 2 3 4 5 6 7 8 9] Explanation: As we have to print numbers between ...

**Question 164. Maximum number of segments of lengths a, b and c** The problem “Maximum number of segments of lengths a, b and c” states that you are given a positive integer N, and you need to find the maximum number of segments of lengths a,b, and c that can be formed using N. Example N = 7 a = 5, b ...

**Question 165. A Space Optimized DP solution for 0-1 Knapsack Problem** Problem Statement We are given a knapsack which can hold some weight, we need to pick some of the items out of given items with some value. The items should be picked such that the value of the knapsack ( total value of picked up items ) should be maximized. ...

**Question 166. K-th Distinct Element in an Array** You are given an integer array A, print k-th distinct element in an array. The given array may contain duplicates and the output should print k-th distinct element among all unique elements in an array. If k is more than a number of distinct elements, then report it. Example Input: ...

**Question 167. Intersection of Two Arrays** In intersection of two arrays problem, we have given two arrays, we need to print their intersection(common elements). Example Input arr1[] = {1, 2, 2, 1} arr2[] = {2, 2} Output {2, 2} Input arr1 = {4, 9, 5} arr2 = {9, 4, 9, 8, 4} Output {4, 9} Algorithm ...

**Question 168. Leetcode Permutations** In this leetcode problem premutation we have given an array of distinct integers, print all of its possible permutations. Examples Input arr[] = {1, 2, 3} Output 1 2 3 1 3 2 2 1 3 2 3 1 3 1 2 3 2 1 Input arr[] = {1, 2, ...

**Question 169. Merge K Sorted Linked Lists** Merge K sorted linked lists problem is so famous as per the interview point of view. This question asks so many times in big companies like Google, Microsoft, Amazon, etc. As the name suggests we’ve been provided with k sorted linked lists. We have to merge them together into a ...

**Question 170. Find Median from data Stream** In Find Median from the data Stream problem, we have given that integers are being read from a data stream. Find the median of all the elements read so far starting from the first integer till the last integer. Example Input 1: stream[ ] = {3,10,5,20,7,6} Output : 3 6.5 ...

**Question 171. Sliding Window Maximum** In Sliding Window Maximum problem we have given an array nums, for each contiguous window of size k, find the maximum element in the window. Example Input nums[] = {1,3,-1,-3,5,3,6,7} k = 3 Output {3,3,5,5,6,7} Explanation Naive Approach for Sliding Window Maximum For every contiguous window of size k, traverse ...

**Question 172. Word Break** Word Break is a problem that beautifully illustrates a whole new concept. We have all heard of compound words. Words made up of more than two words. Today we have a list of words and all we’ve got to do is check if all the words from the dictionary can ...

**Question 173. Reverse Nodes in K-Group** Problem In Reverse Nodes in K-Group problem we have given a linked list, Reverse the linked list in a group of k and return the modified list. If the nodes are not multiple of k then reverse the remaining nodes. The value of k is always smaller or equal to ...

**Question 174. LRU Cache Implementation** Least Recently Used (LRU) Cache is a type of method which is used to maintain the data such that the time required to use the data is the minimum possible. LRU algorithm used when the cache is full. We remove the least recently used data from the cache memory of ...

**Question 175. N queen problem** N queen problem using the concept of Backtracking. Here we place queen such that no queen under attack condition. The attack condition of the queens is if two queens are on the same column, row, and diagonal then they are under attack. Let’s see this by the below figure. Here ...