Founded in 2003, LinkedIn connects the world’s professionals to make them more productive and successful. With more than 850 million members worldwide, including executives from every Fortune 500 company, LinkedIn is the world’s largest professional network. The company has a diversified business model with revenue coming from Talent Solutions, Marketing Solutions, Sales Solutions and Premium Subscriptions products. Headquartered in Silicon Valley, LinkedIn has offices across the globe.

It has got a 4.5* 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 questions collected from LinkedIn Interview Experience for the interview. We have collected past frequently asked questions from LinkedIn Interview Experience for your reference.

Categories of Questions

## LinkedIn Array Questions

**Question 1. 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 2. 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 3. K Closest Points to Origin Leetcode Solution** Problem Statement The K Closest Points to Origin LeetCode Solution – “K Closest Points to Origin” states that given an array of points, x coordinates and y coordinates represent the coordinates on XY Plane. We need to find k closest points to the origin. Note that the distance between two ...

**Question 4. 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 5. Shortest Word Distance Leetcode Solution** Problem Statement The Shortest Word Distance LeetCode Solution – says that you’re given an array of strings and two different words. We need to return the shortest distance between these two words that appear in the input string. Example: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "coding", word2 = "practice" Output: 3 Explanation: Word “coding” occurs at position 4. ...

**Question 6. Insert Interval Leetcode Solution** The problem Insert Interval Leetcode Solution provides us with a list of some intervals and one separate interval. Then we are told to insert this new interval among the list of intervals. So, the new interval might be intersecting with intervals that are already in the list, or it might ...

**Question 7. 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 8. 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 9. Sum of All Odd Length Subarrays Leetcode Solution** Problem Statement In this problem an array of positive integers is given. We have to calculate and return a single integer, the sum of all possible odd length subarrays of the given array. A subarray is a contiguous subsequence of the array. Example arr = [1,4,2,5,3] 58 Explanation: The odd-length subarrays of ...

**Question 10. 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 11. 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 12. 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 13. Segregate even and odd numbers** Problem Statement Suppose you have an integer array. The problem “Segregate even and odd numbers” asks to rearrange the array so that the odd and even numbers can be separated in two segments of the array. The even numbers be shifted into the left side of the array and odd ...

**Question 14. Rearrange array such that even positioned are greater than odd** Problem Statement Suppose you have an integer array. The problem “Rearrange array such that even positioned are greater than odd” asks to rearrange the array such the elements at even position in an array should be greater than the element just before it. Arr[i-1] < = Arr[i], if position ‘i’ ...

**Question 15. Convert an array to reduced form** Problem Statement Problem “Convert an array to reduced form” states that you are given an array of integers of size n distinct elements. The problem statement asked to reduce the array in such a way that the new numbers be placed in the array within the range 0 to n-1. ...

**Question 16. Collect maximum points in a grid using two traversals** Problem Statement We are given a matrix of size “n x m”, and we need to collect maximum points in a grid using two traversals. If we are standing at cell i,j then we have three options to go to cell i+1, j or i+1, j-1or i+1, j+1. That is ...

**Question 17. Cumulative Frequency of Count of Each Element in an Unsorted Array** We are given an unsorted array. The task is to calculate the cumulative frequency of count of each element in an unsorted array. Example Input: A[]={2,4,3,2,2,3,4} Output: Cumulative frequency of 2 in the array is: 3 Cumulative frequency of 3 in the array is: 5 Cumulative frequency of 4 in ...

**Question 18. Find the Only Repetitive Element Between 1 to N-1** In finding the only repetitive element between 1 to N-1 problem we have given an array of random integers within a range from 1 to n-1. There will be one number that is repeated. Your task is to find that number. Example Input [2,3,4,5,2,1]A Output 2 Explanation 2 is the ...

**Question 19. 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 20. Merge Sorted Array** In merge sorted array problem we have given two sorted arrays in increasing order. In input first, we have given the number initialized to array1 and array2. These two-number are N and M. The size of array1 is equal to the sum of N and M. In array 1 first ...

**Question 21. 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 22. Maximum Product Subarray II** Problem Statement In the “Maximum Product Subarray II” problem we have given an array consisting of positive, negative integers, and also zeroes. We need to find the maximum product of the subarray. Input Format The first line containing an integer N. Second-line containing N space-separated integers. Output Format The only ...

**Question 23. Count Possible Triangles** Problem Statement In count possible triangles problem we have given an array of n positive integers. Find the number of triangles that can be formed using three different elements of the array as the sides of a triangle. Note: The condition of the triangle is the sum of two sides ...

**Question 24. Maximum Circular Subarray Sum** Problem Statement In the maximum circular subarray sum problem, we have given an array of integers arranged in a circle, find the maximum sum of consecutive numbers in the circular array. Example Input arr[] = {13, -17, 11, 9, -4, 12, -1} Output 40 Explanation Here, sum = 11 + ...

**Question 25. The Celebrity Problem** Problem Statement In the celebrity problem there is a room of N people, Find the celebrity. Conditions for Celebrity is- If A is Celebrity then Everyone else in the room should know A. A shouldn’t know anyone in the room. We need to find the person who satisfies these conditions. ...

**Question 26. 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 27. 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 28. 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 29. Find Pythagorean Triplets from Array** Problem Statement We have given an array that contains n integers. We need to find the set of Pythagorean triples from the given array. Note: Pythagorean triplets condition: a^2 + b^2 = c^2. Example Input 6 [3, 4, 6, 5, 7, 8] Output Pythagorean triplets: 3, 4, 5 Approach 1 ...

**Question 30. 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 31. 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 32. 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 ...

## LinkedIn String Questions

**Question 33. Rotate String LeetCode Solution** Problem Statement Rotate String LeetCode Solution – Given two strings s and goal, return true if and only if s can become goal after some number of shifts on s. A shift on s consists of moving the leftmost character of s to the rightmost position. For example, if s = “abcde”, then it will ...

**Question 34. Minimum Remove to Make Valid Parentheses LeetCode Solution** Problem Statement The Minimum Remove to Make Valid Parentheses LeetCode Solution – You are given a string s of ‘(‘, ‘)’ and lowercase English characters. Your task is to remove the minimum number of parentheses ( ‘(‘ or ‘)’, in any positions ) so that the resulting parentheses string is ...

**Question 35. Valid Parentheses Leetcode Solution** Problem Statement The Valid Parentheses LeetCode Solution – “Valid Parentheses” states that you’re given a string containing just the characters '(', ')', '{', '}', '[' and ']'. We need to determine whether the input string is a valid string or not. A string is said to be a valid string if open brackets must be closed ...

**Question 36. Shortest Word Distance Leetcode Solution** Problem Statement The Shortest Word Distance LeetCode Solution – says that you’re given an array of strings and two different words. We need to return the shortest distance between these two words that appear in the input string. Example: Input: wordsDict = ["practice", "makes", "perfect", "coding", "makes"], word1 = "coding", word2 = "practice" Output: 3 Explanation: Word “coding” occurs at position 4. ...

**Question 37. Isomorphic Strings Leetcode Solution** Problem Statement In this problem, we are given two strings, a and b. Our goal is to tell whether the two strings are isomorphic or not. Two strings are called isomorphic if and only if the characters in the first string can be replaced by any character(including itself) at all ...

**Question 38. Roman to Integer Leetcode Solution** In the problem “Roman to Integer”, we are given a string representing some positive integer in its Roman numeral form. Roman numerals are represented by 7 characters that can be converted to integers using the following table: Note: The integer value of the given roman numeral will not exceed or ...

**Question 39. Integer to Roman Leetcode Solution** In this problem, we are given an integer and are required to convert into roman numeral. Thus the problem is generally referred to as “Integer to Roman” and this is Integer to Roman Leetcode Solution. If someone does not know about Roman numerals. In the old times, people did not ...

**Question 40. Text Justification LeetCode Solution** We will discuss Text Justification LeetCode Solution today Problem Statement The problem “Text Justification” states that you are given a list s[ ] of type string of size n and an integer size. Justify the text such that each line of text consists of size number of characters. You can ...

**Question 41. Valid Number** In the Valid Number problem we have given a string, check if it can be interpreted into a valid decimal number. It is to be noted that, for a given string to be interpreted as a valid decimal number. It should contain the following characters: Numbers 0-9 Exponent – “e” ...

**Question 42. Count Number of Substrings with K Distinct Character’s** Problem Statement In the “Count Number of Substrings with K Distinct Character’s” problem, we have given a string “s” which has only lowercase alphabets and an integer value k. Write a program that will print the number of possible substrings that have exactly k distinct characters. Input Format The first ...

**Question 43. 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 ...

## LinkedIn Tree Questions

**Question 44. Lowest Common Ancestor of a Binary Search Tree Leetcode Solution** Problem Statement: Lowest Common Ancestor of a Binary Search Tree Leetcode Solution – Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST. Note: “The lowest common ancestor is defined between two nodes p and q as the lowest node in T that has both p and q as ...

**Question 45. 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 46. Symmetric Tree Leetcode Solution** Problem Statement The Symmetric Tree LeetCode Solution – “Symmetric Tree” states that given the root of the binary tree and we need to check if the given binary tree is a mirror of itself (symmetric around its center) or not? If Yes, we need to return true otherwise, false. Example: ...

**Question 47. Check if a given array can represent Preorder Traversal of Binary Search Tree** The problem “Check if a given array can represent Preorder Traversal of Binary Search Tree” states that you are given a preorder traversal sequence. Now consider this sequence and find out if this sequence can represent a binary search tree or not? The expected time complexity for the solution is ...

**Question 48. Find distance between two nodes of a Binary Tree** Problem Statement The problem “Find distance between two nodes of a Binary Tree” states that you are given a binary tree and you are given two nodes. Now you need to find the minimum distance between these two nodes. Example // Tree is shown using the image above node 1 ...

**Question 49. Lowest Common Ancestor** Given the root of a binary tree and two nodes n1 and n2, find the LCA(Lowest Common Ancestor) of the nodes. Example What is Lowest Common Ancestor(LCA)? The ancestors of a node n are the nodes present in the path between root and node. Consider the binary tree shown in ...

**Question 50. Lowest Common Ancestor in Binary Search Tree** Given the root of a binary search tree and two nodes n1 and n2, find the LCA(Lowest Common Ancestor) of the nodes in a given binary search tree. Example Naive Approach for Lowest Common Ancestor in Binary Search Tree Find the LCA(n1, n2) using the optimal approach to find LCA ...

## LinkedIn Graph Questions

**Question 51. 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 ...

**Question 52. Find the smallest binary digit multiple of given number** Problem Statement The problem “Find the smallest binary digit multiple of given number” states that you are given a decimal number N. So find the smallest multiple of N that contains only the binary digits ‘0’ and ‘1’. Example 37 111 A detailed explanation can be found below in the ...

**Question 53. Minimum Steps to reach target by a Knight** Description The problem “Minimum Steps to reach target by a Knight” states that you are given a square chess board of N x N dimensions, co-ordinates of the Knight piece, and the target cell. Find out the minimum number of steps taken by the Knight piece to reach the target ...

## LinkedIn Stack Questions

**Question 54. Minimum Remove to Make Valid Parentheses LeetCode Solution** Problem Statement The Minimum Remove to Make Valid Parentheses LeetCode Solution – You are given a string s of ‘(‘, ‘)’ and lowercase English characters. Your task is to remove the minimum number of parentheses ( ‘(‘ or ‘)’, in any positions ) so that the resulting parentheses string is ...

**Question 55. Valid Parentheses Leetcode Solution** Problem Statement The Valid Parentheses LeetCode Solution – “Valid Parentheses” states that you’re given a string containing just the characters '(', ')', '{', '}', '[' and ']'. We need to determine whether the input string is a valid string or not. A string is said to be a valid string if open brackets must be closed ...

**Question 56. Maximum Frequency Stack Leetcode Solution** Problem Statement The Maximum Frequency Stack LeetCode Solution – “Maximum Frequency Stack” asks you to design a frequency stack in which whenever we pop an element from the stack, it should return the most frequent element present in the stack. Implement the FreqStack class: FreqStack() constructs an empty frequency stack. void push(int val) pushes ...

**Question 57. Check if a given array can represent Preorder Traversal of Binary Search Tree** The problem “Check if a given array can represent Preorder Traversal of Binary Search Tree” states that you are given a preorder traversal sequence. Now consider this sequence and find out if this sequence can represent a binary search tree or not? The expected time complexity for the solution is ...

**Question 58. The Celebrity Problem** Problem Statement In the celebrity problem there is a room of N people, Find the celebrity. Conditions for Celebrity is- If A is Celebrity then Everyone else in the room should know A. A shouldn’t know anyone in the room. We need to find the person who satisfies these conditions. ...

## LinkedIn Queue Questions

**Question 59. Minimum Steps to reach target by a Knight** Description The problem “Minimum Steps to reach target by a Knight” states that you are given a square chess board of N x N dimensions, co-ordinates of the Knight piece, and the target cell. Find out the minimum number of steps taken by the Knight piece to reach the target ...

## LinkedIn Matrix Questions

**Question 60. Collect maximum points in a grid using two traversals** Problem Statement We are given a matrix of size “n x m”, and we need to collect maximum points in a grid using two traversals. If we are standing at cell i,j then we have three options to go to cell i+1, j or i+1, j-1or i+1, j+1. That is ...

**Question 61. The Celebrity Problem** Problem Statement In the celebrity problem there is a room of N people, Find the celebrity. Conditions for Celebrity is- If A is Celebrity then Everyone else in the room should know A. A shouldn’t know anyone in the room. We need to find the person who satisfies these conditions. ...

## LinkedIn Other Questions

**Question 62. 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 63. 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 64. Break a Palindrome LeetCode Solution** Problem Statement: Break a Palindrome LeetCode Solution: Given a palindromic string of lowercase English letters palindrome, replace exactly one character with any lowercase English letter so that the resulting string is not a palindrome and that it is the lexicographically smallest one possible. Return the resulting string. If there is no way to replace a character to make ...

**Question 65. 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 66. Paint House LeetCode Solution** Problem Statement Paint House LeetCode Solution – There is a row of n houses, where each house can be painted one of three colors: red, blue, or green. The cost of painting each house with a certain color is different. You have to paint all the houses such that no ...

**Question 67. Closest Binary Search Tree Value II LeetCode Solution** Problem Statement: Closest Binary Search Tree Value II LeetCode Solution: Given the root of a binary search tree, a target value, and an integer k, return the k values in the BST that are closest to the target. You may return the answer in any order. You are guaranteed to have only one unique set of k values in the BST that are closest ...

**Question 68. Isomorphic Strings LeetCode Solution** Problem Statement Isomorphic Strings LeetCode Solution – Given two strings s and t, determine if they are isomorphic. Two strings s and t are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the ...

**Question 69. 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 70. Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution** Problem Statement: Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution: RandomizedCollection is a data structure that contains a collection of numbers, possibly duplicates (i.e., a multiset). It should support inserting and removing specific elements and also removing a random element. Implement the RandomizedCollection class: RandomizedCollection() Initializes the empty RandomizedCollection object. bool insert(int val) Inserts an item val into ...

**Question 71. 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 72. 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 73. 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 74. 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 75. Can Place Flowers LeetCode Solution** Problem Statement Can Place Flowers LeetCode Solution – You have a long flowerbed in which some of the plots are planted, and some are not. However, flowers cannot be planted in adjacent plots. Given an integer array flowerbed containing 0‘s and 1‘s, where 0 means empty and 1 means not empty, and an integer n, return if n new flowers can be planted in ...

**Question 76. 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 77. Evaluate Reverse Polish Notation LeetCode Solution** Problem Statement Evaluate Reverse Polish Notation LeetCode Solution – Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, and /. Each operand may be an integer or another expression. Note that the division between two integers should truncate toward zero. It is guaranteed that the given ...

**Question 78. Nested List Weight Sum II LeetCode Solution** Problem Statement Nested List Weight Sum II LeetCode Solution – You are given a nested list of integers nestedList. Each element is either an integer or a list whose elements may also be integers or other lists. The depth of an integer is the number of lists that it is inside of. For ...

**Question 79. 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 80. 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 81. 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 82. 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 83. 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 84. 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 85. Product of Array Except Self LeetCode Solution** Problem Statement Product of Array Except Self LeetCode Solution – Given an integer array nums, return an array answer such that answer[i] is equal to the product of all the elements of nums except nums[i]. The product of any prefix or suffix of nums is guaranteed to fit in a 32-bit integer. You must write an algorithm that runs in O(n) time and without using the division ...

**Question 86. 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 87. Find Largest Value in Each Tree Row LeetCode Solution** Problem Statement Find Largest Value in Each Tree Row LeetCode Solution – Given the root of a binary tree, return an array of the largest value in each row of the tree (0-indexed). Example Test Case 1: Input: root = [1, 3, 4, 5, 3, null, 9] Output: [1, 3, 9] Explanation 1, 3, and ...

**Question 88. Convert to Base -2 LeetCode Solution** Problem Statement Convert to Base -2 LeetCode Solution – Given an integer n, return a binary string representing its representation in base -2. Note that the returned string should not have leading zeros unless the string is "0". Input: n = 2 Output: "110" Explantion: (-2)2 + (-2)1 = 2 Explanation The logic is ...

**Question 89. Kth Smallest Element in a BST Leetcode Solution** Problem Statement Kth Smallest Element in a BST Leetcode Solution – Given the root of a binary search tree, and an integer k, return the kth smallest value (1-indexed) of all the values of the nodes in the tree. Examples: Input: root = [3,1,4,null,2], k = 1 Output: 1 Input: root = [5,3,6,2,4,null,null,1], k ...

**Question 90. Find Leaves of Binary Tree LeetCode Solution** Problem Statement Find Leaves of Binary Tree LeetCode Solution – Given the root of a binary tree, collect a tree’s nodes as if you were doing this: Collect all the leaf nodes. Remove all the leaf nodes. Repeat until the tree is empty. Example Test Case 1: Input: root = [1, 2, 3, ...

**Question 91. 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 92. String to Integer (atoi) LeetCode Solution** Problem Statement The String to Integer (atoi) Leetcode Solution -“String to Integer (atoi)” states that Implementing the myAtoi(string s) function, which converts a string to a 32-bit signed integer (similar to C/C++’s atoi function). The algorithm for myAtoi(string s) is as follows: Read in and ignore any leading whitespace. Check if the next character (if ...

**Question 93. Graph Valid Tree LeetCode Solution** Problem Statement Graph Valid Tree LeetCode Solution – Given the edges of a graph, check if the edges make up a valid tree. If yes, return true and false otherwise. The edges are given as a 2D array of size n*2 Examples & Explanations Example 1: Input: n = 5, ...

**Question 94. Kth Smallest Product of Two Sorted Arrays LeetCode Solution** Problem Statement Kth Smallest Product of Two Sorted Arrays LeetCode Solution – Given two sorted 0-indexed integer arrays nums1 and nums2 as well as an integer k, return the kth (1-based) smallest product of nums1[i] * nums2[j] where 0 <= i < nums1.length and 0 <= j < nums2.length. Input: nums1 = [2,5], nums2 = [3,4], k = 2 Output: 8 Explanation: The 2 ...

**Question 95. Valid Perfect Square LeetCode Solution** Problem Statement Valid Perfect Square LeetCode Solution – Given a positive integer num, write a function that returns True if num is a perfect square else False. Follow up: Do not use any built-in library function such as sqrt. Input: num = 16 Output: true Explanation A boundary for our solution is fixed. for any number ...

**Question 96. Subarray Product Less Than K LeetCode Solution** Problem Statement Subarray Product Less Than K LeetCode Solution – Given an array of integers nums and an integer k, return the number of contiguous subarrays where the product of all the elements in the subarray is strictly less than k. Example Test Case 1: Input: inputArr = [10, 5, 2, 6] k = 100 ...

**Question 97. Edit Distance LeetCode Solution** Problem Statement The problem Edit Distance LeetCode Solution states that you are given two strings word1 and word2 and you need to convert word1 into word2 in minimum operations. The operations that can be performed on the string are – Insert a character Delete a character Replace a character Examples Test Case ...

**Question 98. Longest Substring with At Most K Distinct Characters LeetCode Solution** Problem Statement Longest Substring with At Most K Distinct Characters LeetCode Solution – Given a string S and an integer K, return the length of the longest substring of S that contains at most K distinct characters. Example: Test Case 1: Input: S = “bacc” K = 2 Output: 3 Test Case 2: Input: S = “ab” ...

**Question 99. 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 100. Same Tree LeetCode Solution** Problem Statement The problem Same Tree says Given the roots of two binary trees p and q, write a function to check if they are the same or not. Two binary trees are considered the same if they are structurally identical, and the nodes have the same value. Example: Test Case ...

**Question 101. Remove Duplicates from Sorted Array Leetcode Solution** Problem Statement The Remove Duplicates from Sorted Array Leetcode Solution – says that you’re given an integer array sorted in non-decreasing order. We need to remove all duplicate elements and modify the original array such that the relative order of distinct elements remains the same and, report the value of ...

**Question 102. Bulb Switcher LeetCode Solution** Problem Statement Bulb Switcher LeetCode Solution – There are n bulbs that are initially off. You first turn on all the bulbs, then you turn off every second bulb. In the third round, you toggle every third bulb (turning on if it’s off or turning off if it’s on). For the ith round, you ...

**Question 103. 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 104. 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 105. Number of Islands LeetCode Solution** Problem Statement The number of Islands LeetCode Solution – “Number of Islands” states that you are given an m x n 2D binary grid which represents a map of ‘1’s (land) and ‘0’s (water), you have to return the number of islands. An island is surrounded by water and is ...

**Question 106. Rotate List Leetcode Solution** The problem Rotate List Leetcode Solution provides us a linked list and an integer. We are told to rotate the linked list to the right by k places. So if we rotate a linked list k places to the right, in each step we take the last element from the ...

**Question 107. Pow(x, n) Leetcode Solution** The problem “Pow(x, n) Leetcode Solution” states that you are given two numbers, one of which is a floating-point number and another an integer. The integer denotes the exponent and the base is the floating-point number. We are told to find the value after evaluating the exponent over the base. ...

**Question 108. 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 109. Find missing elements of a range** The problem Find missing elements of a range” states that you are given an array of distinct elements within a particular range and a range given as low and high. Find all the missing elements within a range which is not present in an array. The output should be in ...

**Question 110. Boolean Parenthesization Problem** Problem Statement “ Boolean Parenthesization Problem ” states that we are given a sequence of true and false, and some boolean operators( AND, OR, XOR) in between them. We need to find the number of ways to parenthesize the given sequence such that the entire sequence results in TRUE. In ...

**Question 111. 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: ...