**PayPal Holdings, Inc.** is an American multinational financial technology company operating an online payments system in the majority of countries that support online money transfers, and serves as an electronic alternative to traditional paper methods such as checks and money orders. The company operates as a payment processor for online vendors, auction sites and many other commercial users, for which it charges a fee.

It has got a 4.2* 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 **PayPal **Interview Questions for the interview. We have collected past frequently asked **PayPal **Interview Questions for your reference.

Categories of Questions

## PayPal Array Questions

**Question 1. 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 2. 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 3. 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 4. Moving Average from Data Stream Leetcode Solution** Problem Statement The Moving Average from Data Stream LeetCode Solution – “Moving Average from Data Stream” states that given a stream of integers and a window size k. We need to calculate the moving average of all the integers in the sliding window. If the number of elements in the ...

**Question 5. Missing Number Leetcode Solution** Problem Statement The Missing Number LeetCode Solution – “Missing Number” states that given an array of size n containing n distinct numbers between [0,n]. We need to return the number which is missing in the range. Example: Input: nums = [3,0,1] Output: 2 Explanation: We can easily observe that all the ...

**Question 6. 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 7. 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 8. Sqrt (or Square Root) Decomposition Technique** You are given query of range an integer array. You will be asked to determine the sum of all the numbers that come in the range of given query. The query given is of two types, that are – Update: (index, value) is given as a query, where you need ...

**Question 9. Segregate 0s and 1s in an Array** Problem Statement Suppose you have an integer array. The problem “Segregate 0s and 1s in an array” asks to segregate the array in two parts, in 0s and in 1s. The 0’s should be on the left side of the array and 1’s on the right side of the array. ...

**Question 10. Maximum subsequence sum such that no three are consecutive** The problem “Maximum subsequence sum such that no three are consecutive ” states that you are given an array of integers. Now you need to find a subsequence that has the maximum sum given that you cannot consider three consecutive elements. To recall, a subsequence is nothing but an array ...

**Question 11. Minimum sum of multiplications of n numbers** The problem “Minimum sum of multiplications of n numbers” states that you are given n integers and you need to minimize the sum of multiplication of all the numbers by taking two elements that are adjacent at a time and putting back their sum mod 100 until a single number ...

**Question 12. Generate all possible sorted arrays from alternate elements of two given sorted arrays** The problem “Generate all possible sorted arrays from alternate elements of two given sorted arrays” states that suppose you have two sorted arrays. The problem statement asks to find out all the possible sorted arrays, such that number should be arranged alternatively from the two given different arrays. Example ArrA[] ...

**Question 13. Range Queries for Longest Correct Bracket Subsequence** You are given a sequence of some brackets subsequence, in other words, you are given brackets like ‘(’ and ‘)’ and you are given a query range as a starting point and ending point. The problem “Range Queries for Longest Correct Bracket Subsequence” asks to find out the maximum length ...

**Question 14. Range LCM Queries** Problem Statement The problem “Range LCM Queries” states that you have an integer array and q number of queries. Each query contains the (left, right) as a range. The given task is to find out the LCM(left, right), i.e, LCM of all the number that comes in the range of ...

**Question 15. Number of elements less than or equal to a given number in a given subarray** Problem Statement The problem “Number of elements less than or equal to a given number in a given subarray” states that you are given an integer array and q number of queries. There will be two types of queries à queryUpdate(i, v): There will be two integers i and v, ...

**Question 16. GCDs of given index ranges in an array** Problem Statement The problem ‘GCDs of given index ranges in an array” states that you are given an integer array and some range queries. The problem statement asks to find out the Greatest Common Divisor of the sub-array so formed within the range. Example arr[] = {10, 5, 18, 9, ...

**Question 17. Queries for GCD of all numbers of an array except elements in a given range** Problem Statement The “Queries for GCD of all numbers of an array except elements in a given range” problem states that you will be given an integer array and a q number of queries. Each query contains the number left and right. The problem statement asks to find out the ...

**Question 18. 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 19. Replace two consecutive equal values with one greater** Problem Statement Suppose you have an integer array. The problem “Replace two consecutive equal values with one greater” asks to replace all those pair values say ‘a’ which comes consecutively with a number “a+1” 1 greater than them (two consecutive numbers), such that even after the modification or repetition there ...

**Question 20. First negative integer in every window of size k** Problem Statement The problem “First negative integer in every window of size k” states that you are given an array containing positive and negative integers, for every window of size k print the first negative integer in that window. If there is no negative integer in any window then output ...

**Question 21. Find the minimum distance between two numbers** Problem Statement You have given an array and two numbers called x and y. The problem “Find the minimum distance between two numbers” asks to find out the minimum possible distance between them. The array given can have common elements. You can assume that both x and y are different. ...

**Question 22. Largest area rectangular sub-matrix with equal number of 1’s and 0’s** Problem Statement Given a binary matrix of size n x m. The problem is to find the largest area rectangular sub-matrix with equal number of 1’s and 0’s. Example Dimensions = 4 x 4 Matrix: 1 1 1 1 0 1 0 1 1 0 1 0 1 0 0 ...

**Question 23. Largest rectangular sub-matrix whose sum is 0** Problem Statement Find the maximum size sub-matrix in a 2D array whose sum is zero. A sub-matrix is nothing but a 2D array inside of the given 2D array. So, you have a matrix of signed integers, you need to calculate the sum of sub-matrices and find the matrix with ...

**Question 24. Maximal Square** In the maximal square problem we have given a 2D binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s, and return its area. Example Input: 1 0 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 1 0 ...

**Question 25. Merge Overlapping Intervals** In merge overlapping intervals problem we have given a collection of intervals, merge and return all overlapping intervals. Example Input : [[2, 3], [3, 4], [5, 7]] Output: [[2, 4], [5, 7]] Explanation: We can merge [2, 3] and [3, 4] together to form [2, 4] Approach for finding Merge ...

**Question 26. 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 27. 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 28. 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 29. Merging Intervals** In merging intervals problem we have given a set of intervals of the form [l, r], merge the overlapping intervals. Examples Input {[1, 3], [2, 6], [8, 10], [15, 18]} Output {[1, 6], [8, 10], [15, 18]} Input {[1, 4], [1, 5]} Output {[1, 5]} Naive Approach for merging intervals ...

**Question 30. Stock Buy Sell to Maximize Profit** Problem Statement In the “Stock Buy Sell to Maximize Profit” problem we have given an array that contains stock price on each day, find the maximum profit that you can make by buying and selling in those days. Here, we can buy and sell multiple times but only after selling ...

**Question 31. Merge Overlapping Intervals II** Problem Statement In the “Merge Overlapping Intervals II” problem we have given a set of intervals. Write a program that will merge the overlapping intervals into one and print all the non-overlapping intervals. Input Format The first line containing an integer n. Second-line containing n pairs where each pair is ...

**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. Find the Maximum Repeating Number in Array** Problem Statement In the “Find the Maximum Repeating Number in Array” problem we have given an unsorted array of size N. Given array contains numbers in range {0, k} where k <= N. Find the number that is coming the maximum number of times in the array. Input Format The ...

**Question 34. Find the Lost Element From a Duplicated Array** Problem Statement Given two arrays A and B, one array is a duplicate of the other except one element. The one element is missing from either A or B. we need to find the lost element from a duplicated array. Example 5 1 6 4 8 9 6 4 8 ...

**Question 35. 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 36. Find Element Using Binary Search in Sorted Array** Problem Statement Given a sorted array, Find element using binary search in the sorted array. If present, print the index of that element else print -1. Example Input arr[] = {1, 6, 7, 8, 9, 12, 14, 16, 26, 29, 36, 37, 156} X = 6 //element to be searched ...

**Question 37. 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 38. 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 39. Find Smallest Missing Number in a Sorted Array** Problem Statement In the “Find Smallest Missing Number in a Sorted Array” problem we have given an integer array. Find the smallest missing number in N sized sorted array having unique elements in the range of 0 to M-1, where M>N. Example Input [0, 1, 2, 3, 4, 6, 7, ...

**Question 40. First Repeating Element** Problem Statement We have given an array that contains n integers. We have to find the first repeating element in the given array. If there is no repeated element then print “No repeating integer found”. Note: Repeating elements are those elements that come more than once. (Array may contain duplicates) ...

**Question 41. 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 42. Find the first Repeating Number in a Given Array** Problem Statement There can be multiple repeating numbers in an array but you have to find the first repeating number in a given array (occurring the second time). Example Input 12 5 4 2 8 9 7 12 5 6 12 4 7 Output 5 is the first repeating element ...

**Question 43. Find the Missing Number** Problem Statement In finding the missing number from an array of 1 to N numbers we have given an array that contains N-1 numbers. One number is missing from an array of numbers from 1 to N. We have to find the missing number. Input Format First-line containing an integer ...

## PayPal String Questions

**Question 44. Longest Substring Without Repeating Characters Leetcode Solution** Problem Statement The Longest Substring Without Repeating Characters LeetCode Solution – states that given the string s. We need to find the longest substring without repeating characters. Example: Input: s = "abcabcbb" Output: 3 Explanation: The longest substring with no characters being repeated is of length 3. The string is: “abc”. Input: s = "bbbbb" ...

**Question 45. Destination City Leetcode Solution** The problem Destination City Leetcode Solution provides us with some relations between cities. The input is given as line separated pair of cities. Each line in input denotes a direct road from the starting point to the endpoint. It is given in the problem, that the cities do not form ...

**Question 46. 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 47. 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 48. Zigzag Conversion** In the Zigzag Conversion problem, we have given a string s of length n and an integer r representing the number of rows. Convert the given string in the zigzag pattern of r rows and concatenate the characters row-wise. Print the new concatenated string. Example Input : s = “TutorialCup” ...

## PayPal Tree Questions

**Question 49. 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 50. Write Code to Determine if Two Trees are Identical** The problem “Write Code to Determine if Two Trees are Identical” states that you are given two binary trees. find out if they are identical or not? Here, identical tree means that both the binary trees have the same node value with the same arrangement of nodes. Example Both trees ...

**Question 51. Range LCM Queries** Problem Statement The problem “Range LCM Queries” states that you have an integer array and q number of queries. Each query contains the (left, right) as a range. The given task is to find out the LCM(left, right), i.e, LCM of all the number that comes in the range of ...

**Question 52. Number of elements less than or equal to a given number in a given subarray** Problem Statement The problem “Number of elements less than or equal to a given number in a given subarray” states that you are given an integer array and q number of queries. There will be two types of queries à queryUpdate(i, v): There will be two integers i and v, ...

**Question 53. GCDs of given index ranges in an array** Problem Statement The problem ‘GCDs of given index ranges in an array” states that you are given an integer array and some range queries. The problem statement asks to find out the Greatest Common Divisor of the sub-array so formed within the range. Example arr[] = {10, 5, 18, 9, ...

**Question 54. Check if each internal node of a BST has exactly one child** Problem Statement “Check if each internal node of a BST has exactly one child” problem states that you are given a preorder traversal of a binary search tree. And you need to find if all the non-leaf nodes contain only a single child. Here we also consider that all the ...

## PayPal Stack Questions

**Question 55. 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 56. 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 57. Range Queries for Longest Correct Bracket Subsequence** You are given a sequence of some brackets subsequence, in other words, you are given brackets like ‘(’ and ‘)’ and you are given a query range as a starting point and ending point. The problem “Range Queries for Longest Correct Bracket Subsequence” asks to find out the maximum length ...

**Question 58. Implement Stack using Queues** Implement the following functions of stack data structure using standard operations of queue, push(x) –> Push an element x to the stack pop() –> Removes the element on top of stack top() –> Return the element on top of stack empty() –> Return whether the stack is empty Examples Input: ...

## PayPal Queue Questions

**Question 59. Moving Average from Data Stream Leetcode Solution** Problem Statement The Moving Average from Data Stream LeetCode Solution – “Moving Average from Data Stream” states that given a stream of integers and a window size k. We need to calculate the moving average of all the integers in the sliding window. If the number of elements in the ...

**Question 60. First negative integer in every window of size k** Problem Statement The problem “First negative integer in every window of size k” states that you are given an array containing positive and negative integers, for every window of size k print the first negative integer in that window. If there is no negative integer in any window then output ...

**Question 61. Implement Stack using Queues** Implement the following functions of stack data structure using standard operations of queue, push(x) –> Push an element x to the stack pop() –> Removes the element on top of stack top() –> Return the element on top of stack empty() –> Return whether the stack is empty Examples Input: ...

## PayPal Matrix Questions

**Question 62. 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 63. Largest area rectangular sub-matrix with equal number of 1’s and 0’s** Problem Statement Given a binary matrix of size n x m. The problem is to find the largest area rectangular sub-matrix with equal number of 1’s and 0’s. Example Dimensions = 4 x 4 Matrix: 1 1 1 1 0 1 0 1 1 0 1 0 1 0 0 ...

**Question 64. Largest rectangular sub-matrix whose sum is 0** Problem Statement Find the maximum size sub-matrix in a 2D array whose sum is zero. A sub-matrix is nothing but a 2D array inside of the given 2D array. So, you have a matrix of signed integers, you need to calculate the sum of sub-matrices and find the matrix with ...

**Question 65. Maximal Square** In the maximal square problem we have given a 2D binary matrix filled with 0’s and 1’s, find the largest square containing only 1’s, and return its area. Example Input: 1 0 1 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 1 0 ...

## PayPal Other Questions

**Question 66. 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 67. 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 68. 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 69. 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 70. 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 71. Pairs of Songs With Total Durations Divisible by 60 LeetCode Solution** Problem Statement Pairs of Songs With Total Durations Divisible by 60 LeetCode Solution – Pairs of Songs With Total Durations Divisible by 60 LeetCode Solution says that – You are given a list of songs where the ith song has a duration of time[i] seconds. Return the number of pairs of songs for which ...

**Question 72. Valid Anagram Leetcode Solution** Problem Statement Valid Anagram Leetcode Solution – Given two strings s and t, return true if t is an anagram of s, and false otherwise. 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: Input: s = "anagram", t = "nagaram" Output: ...

**Question 73. 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 74. Next Greater Element I Leetcode Solution** Problem Statement Next Greater Element I Leetcode Solution – The next greater element of some element x in an array is the first greater element that is to the right of x in the same array. You are given two distinct 0-indexed integer arrays nums1 and nums2, where nums1 is a subset of nums2. For each 0 <= i < nums1.length, find the index j such that nums1[i] == nums2[j] and determine ...

**Question 75. 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 76. 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 77. Reverse Words in a String III LeetCode Solution** Problem Statement Reverse Words in a String III LeetCode Solution – We are given a string and are asked to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order. Examples & Explanations Example 1: Input: s = "Let's take LeetCode ...

**Question 78. 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 79. First Unique Character in a String LeetCode Solution** Problem Statement First Unique Character in a String LeetCode Solution – Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1. Example Test Case 1: Input: s = “leetcode” Output: 0 Test Case 2: Input: s = “aabb” Output: -1 Explanation ...

**Question 80. 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 81. Maximum Number of Occurrences of a Substring Leetcode Solution** Problem Statement : Maximum Number of Occurrences of a Substring Leetcode Solution – Given a string s, return the maximum number of occurrences of any substring under the following rules: The number of unique characters in the substring must be less than or equal to maxLetters. The substring size must be between minSize and maxSize inclusive. Example ...

**Question 82. 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 83. Zigzag Conversion LeetCode Solution** Problem Statement Zigzag Conversion LeetCode Solution – The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility) P A H N A P L S I I G Y I ...

**Question 84. Find the Duplicate Number LeetCode Solution** Problem Statement Find the Duplicate Number LeetCode Solution – Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. There is only one repeated number in nums, return this repeated number. You must solve the problem without modifying the array nums and uses only constant extra space. Input: nums = [1,3,4,2,2] Output: 2 Explanation ...

**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. 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 88. 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 89. 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 90. Jump Game Leetcode Solution** Problem Statement Jump Game Leetcode Solution – You are given an integer array nums. You are initially positioned at the array’s first index, and each element in the array represents your maximum jump length at that position. Return true if you can reach the last index, or false otherwise. Example: Input 1: nums = [2, ...

**Question 91. Linked List Cycle II LeetCode Solution** Problem Statement Linked List Cycle II LeetCode Solution – Given the head of a linked list, return the node where the cycle begins. If there is no cycle, return null. There is a cycle in a linked list if there is some node in the list that can be reached again by continuously ...

**Question 92. Number of Provinces Leetcode Solution** Problem Statement Number of Provinces Leetcode Solution – We are given an adjacency matrix representation of a graph and need to find the number of provinces. Here province is a group of directly or indirectly connected cities and no other cities outside of the group. Example Example 1: Input: isConnected ...

**Question 93. Check If Array Pairs Are Divisible by k LeetCode Solution** Problem Statement Check If Array Pairs Are Divisible by k LeetCode Solution – Given an array of integers of even length n and an integer k. We want to divide the array into exactly n/2 pairs such that the sum of each pair is divisible by k. Return true If ...

**Question 94. Remove Nth Node From End of List Leetcode Solution** Problem Statement The Remove Nth Node From End of List Leetcode Solution – states that you are given the head of a linked list and you need to remove the nth node from the end of this list. After deleting this node, return the head of the modified list. Example: Input: ...

**Question 95. 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 96. 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 97. 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 98. Sequences of given length where every element is more than or equal to twice of previous** The problem “Sequences of given length where every element is more than or equal to twice of previous” provides us with two integers m and n. Here m is the largest number that can exist in the sequence and n is the number of elements that must be present in the ...

**Question 99. Count ways to reach the nth stair using step 1, 2 or 3** The problem “Count ways to reach the nth stair using step 1, 2, or 3” states that you are standing on the ground. Now you need to reach the end of the staircase. So how many ways are there to reach the end if you can jump only 1, 2, ...

**Question 100. Tiling Problem** Problem Statement The “Tiling Problem” states that you have a grid of size 2 x N and a tile of size 2 x 1. So, find the number of ways to tile the given grid. Example 3 2 Explanation: Approach for Tiling Problem We can solve this problem by using recursion. ...

**Question 101. Page Replacement Algorithms in Operating Systems** What is Page Replacement? The modern operating systems use paging for memory management and many times there is a need for page replacement. Page replacement is the process of replacing a page that is currently present in the memory with a page that is needed but is not present in ...

**Question 102. Count pairs from two linked lists whose sum is equal to a given value** Problem Statement Problem “Count pairs from two linked lists whose sum is equal to a given value” state that you are given two linked lists and an integer value sum. The problem statement asked to find out how many total pair has a sum equal to the given value. Example ...

**Question 103. How to print maximum number of A’s using given four keys** Problem Statement How to print maximum number of A’s using given four keys, this problem states that you have the option to choose which key to press. The keys perform the following tasks: Key1 – Prints ‘A’ on screen Key2 – Select the whole screen. Key3 – Copy the selected ...

**Question 104. Wiggle Sort** Wiggle Sort!? All my readers must’ve found the name of today’s problem very funny. However, it is a very smart problem that tests our understanding of a varied range of concepts. Let us jump straight to the problem without any further confusion. Example You have an array Input: [1,5,1,6,4] Expected ...

**Question 105. 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 ...