**Paytm **is an Indian digital payments and financial services company, based in Noida.^{} It was founded in 2010 by Vijay Shekhar Sharma under One97 Communications. The company offers mobile payment services to consumers and enables merchants to receive payments through its QR code, point of sale, and online payment gateway offerings.^{} In partnership with financial institutions, Paytm offers financial services such as micro-loans and buy now, pay later to its consumers and merchants.^{} Apart from bill payments and money transfers, the company also provides ticketing services, retail brokerage products, and online games.

It has got a 3.7* 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 **Paytm **Interview Experience for the interview. We have collected past frequently asked questions from **Paytm **Interview Experience for your reference.

Categories of Questions

## Paytm Array Questions

**Question 1. 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 2. 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 3. 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 4. Length of the largest subarray with contiguous elements** The problem “Length of the largest subarray with contiguous elements” states that you are given an integer array. The problem statement asks to find out the length of the longest contiguous sub-array of which elements can be arranged in a sequence (continuous, either ascending or descending). The numbers in the ...

**Question 5. Subarray with 0 sum** The problem “Find if there is a subarray with 0 sum” states that you are given an integer array containing negative integers as well. The problem statement asks to determine if any sub-array of size at-least 1. This sub-array should have a sum equal to 1. Example arr[] = {2,1,-3,4,5} ...

**Question 6. Largest subarray with equal number of 0s and 1s** You are given an array of integers. The integers are only 0 and 1 in the input array. The problem statement asks to find out the largest sub-array that can have equal count of 0s and 1s. Example arr[]={0,1,0,1,0,1,1,1} 0 to 5 (total 6 elements) Explanation From the array position ...

**Question 7. Construction of Longest Increasing Subsequence (N log N)** Problem Statement You are given an array of integers. The problem “Construction of Longest Increasing Subsequence (N log N)” asks to construct the longest increasing subsequence. Example arr[]={1, 4, 7, 2, 9, 6, 12, 3 } 12, 9, 7, 4, 1 and the size of this longest increasing subsequence is ...

**Question 8. 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 9. Arrange given numbers to form the biggest number** Problem Statement Suppose you have an array of integers. The problem “Arrange given numbers to form the biggest number” asks to rearrange the array in such a manner that the output should be the maximum value which can be made with those numbers of an array. Example [34, 86, 87, ...

**Question 10. 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 11. Printing brackets in Matrix Chain Multiplication Problem** Problem Statement We need to find the order of multiplication of matrices such that the number of operations involved in the multiplication of all the matrices is minimized. Then we need to print this order i.e. printing brackets in matrix chain multiplication problem. Consider you have 3 matrices A, B, ...

**Question 12. 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 13. Set Matrix Zeroes** In the set matrix zeroes problem, we have given a (n X m) matrix, if an element is 0, set its entire row and column 0. Examples Input: { [1, 1, 1] [1, 0, 1] [1, 1, 1] } Output: { [1, 0, 1] [0, 0, 0] [1, 0, 1] ...

**Question 14. 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 15. Find the Subarray of given length with Least Average** Problem Statement In the “Find the Subarray of given length with Least Average” problem we have given an array and an input integer X. Write a program to find the subarray of length X with least/minimum average. Prints the starting and ending indexes of the subarray which has the least ...

**Question 16. 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 17. 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 18. Find the Row with Maximum Number of 1’s** Problem Statement In the “Find the Row with Maximum Number of 1’s” problem we have given a matrix(2D array) containing binary digits with each row sorted. Find the row which has the maximum number of 1’s. Input Format The first line containing two integers values n, m. Next, n lines ...

**Question 19. Maximum Element in an Array which is Increasing and then Decreasing** Problem Statement In the given array which contains n elements. Elements are stored in such a way that first k elements are in increasing order and then n-k elements in decreasing from there, we need to find the maximum element in the array. Example a) Input array : [15, 25, ...

**Question 20. Find Duplicates in an Array in Most Efficient Way** Problem Statement Display all the elements which are duplicates in the most efficient way in O(n) and O(1) space. Given an array of size n which contains numbers from range 0 to n-1, these numbers can occur any number of times. Find duplicates in an array in the most efficient ...

**Question 21. Sort 0s 1s and 2s in an Array** Problem Statement Given an array containing N elements where elements of the array are 0,1 or 2. Sort or Segregate 0s 1s and 2s in an array. Arrange all zeros in the first half, all ones in the second half and all twos in the third half. Example Input 22 ...

**Question 22. 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 23. Find Minimum Distance Between Two Numbers in an Array** Problem Statement In the given unsorted array, which may also contain duplicates, find the minimum distance between two different numbers in an array. Distance between 2 numbers in an array: the absolute difference between the indices +1. Example Input 12 3 5 4 2 6 5 6 6 5 4 ...

**Question 24. Maximum Sum of Non Consecutive Elements** Problem Statement In the “Maximum Sum of Non Consecutive Elements” given array, you need to find the maximum sum of non-consecutive elements. You can not add immediate neighbor numbers. For example [1,3,5,6,7,8,] here 1, 3 are adjacent so we can’t add them, and 6, 8 are not adjacent so we ...

**Question 25. 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 ...

## Paytm String Questions

**Question 26. Arrange given numbers to form the biggest number** Problem Statement Suppose you have an array of integers. The problem “Arrange given numbers to form the biggest number” asks to rearrange the array in such a manner that the output should be the maximum value which can be made with those numbers of an array. Example [34, 86, 87, ...

**Question 27. Reverse words in a string** Problem Statement “Reverse words in a string” states that you are given a string s of size n. Print the string in reverse order such that the last word becomes the first, second last becomes the second, and so on. Hereby string we refer to a sentence containing words instead ...

**Question 28. Second Most Repeated Word in a Sequence** Given a sequence of strings, the task is to find out the second most repeated (or frequent) word or string in a sequence. (Considering no two words are the second most repeated, there will be always a single word). Example Input: {“aaa”, ”bb”, ”bb”, ”aaa”, ”aaa”, c”} Output: String with ...

**Question 29. Expression Contains Redundant Bracket or Not** Given a string s containing an expression of operators, operands, and parenthesis. Find if the given string contains any unnecessary parenthesis without which the expression will still give the same result. In other words, we have to find that expression contains a redundant bracket or not. Redundant Bracket If an ...

**Question 30. 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 31. Check if a Linked list of Strings form a Palindrome** Problem Statement In the “Check if a Linked list of Strings form a Palindrome” problem we have given a linked list handling string data. Write a program to check whether the data forms a palindrom or not. Example ba->c->d->ca->b 1 Explanation: In the above example we can see that the ...

## Paytm Tree Questions

**Question 32. Sum Root to Leaf Numbers LeetCode Solution** Problem Statement Sum Root to Leaf Numbers LeetCode Solution says – You are given the root of a binary tree containing digits from 0 to 9 only. Each root-to-leaf path in the tree represents a number. For example, the root-to-leaf path 1 -> 2 -> 3 represents the number 123. Return the total sum of all root-to-leaf numbers. Test ...

**Question 33. Bottom View of a Binary Tree** Problem Statement The problem “Bottom View of a Binary Tree” states that you are given a binary tree and now you need to find the bottom view for the given tree. When we see a tree from the downward direction. The nodes which are visible to us is the bottom ...

**Question 34. Iterative Postorder Traversal Using Two Stacks** Problem Statement The problem “Iterative Postorder Traversal Using Two Stacks” states that you are given a binary tree with n nodes. Write the program for it’s iterative postorder traversal using two stacks. Example Input 4 5 2 6 7 3 1 Input 4 2 3 1 Algorithm Create ...

**Question 35. Iterative method to find ancestors of a given binary tree** Problem Statement “Iterative method to find ancestors of a given binary tree” problem states that you are given a binary tree and an integer representing a key. Create a function to print all the ancestors of the given key using iteration. Example Input key = 6 5 2 1 Explanation: ...

**Question 36. Top View of Binary Tree** The top view of a binary tree is the set of nodes visible when the tree is viewed from the top. Given a binary tree, the Output top view of the binary tree from the left-most horizontal level to the rightmost horizontal level. Example Example 1 Example 2 Types of ...

## Paytm Stack Questions

**Question 37. Design a stack that supports getMin() in O(1) time and O(1) extra space** Design a stack that supports getMin() in O(1) time and O(1) extra space. Thus the special stack data structure must support all the operations of the stack like – void push() int pop() bool isFull() bool isEmpty() in constant time. Add an additional operation getMin() to return the minimum value ...

**Question 38. Iterative Postorder Traversal Using Two Stacks** Problem Statement The problem “Iterative Postorder Traversal Using Two Stacks” states that you are given a binary tree with n nodes. Write the program for it’s iterative postorder traversal using two stacks. Example Input 4 5 2 6 7 3 1 Input 4 2 3 1 Algorithm Create ...

**Question 39. Iterative method to find ancestors of a given binary tree** Problem Statement “Iterative method to find ancestors of a given binary tree” problem states that you are given a binary tree and an integer representing a key. Create a function to print all the ancestors of the given key using iteration. Example Input key = 6 5 2 1 Explanation: ...

**Question 40. Expression Contains Redundant Bracket or Not** Given a string s containing an expression of operators, operands, and parenthesis. Find if the given string contains any unnecessary parenthesis without which the expression will still give the same result. In other words, we have to find that expression contains a redundant bracket or not. Redundant Bracket If an ...

**Question 41. Infix to Postfix** What is an infix expression? Expression in the form of ‘operand’ ‘operator’ ‘operand’ is called infix expression. Example: a+b What is postfix expression? Expression in the form of ‘operand’ ‘operand’ ‘operator’ is called postfix expression. Example: ab+ What is the need of infix to postfix conversion? Infix expression is easy ...

## Paytm Matrix Questions

**Question 42. Printing brackets in Matrix Chain Multiplication Problem** Problem Statement We need to find the order of multiplication of matrices such that the number of operations involved in the multiplication of all the matrices is minimized. Then we need to print this order i.e. printing brackets in matrix chain multiplication problem. Consider you have 3 matrices A, B, ...

**Question 43. Set Matrix Zeroes** In the set matrix zeroes problem, we have given a (n X m) matrix, if an element is 0, set its entire row and column 0. Examples Input: { [1, 1, 1] [1, 0, 1] [1, 1, 1] } Output: { [1, 0, 1] [0, 0, 0] [1, 0, 1] ...

**Question 44. Find the Row with Maximum Number of 1’s** Problem Statement In the “Find the Row with Maximum Number of 1’s” problem we have given a matrix(2D array) containing binary digits with each row sorted. Find the row which has the maximum number of 1’s. Input Format The first line containing two integers values n, m. Next, n lines ...

## Paytm Other Questions

**Question 45. 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 46. Regular Expression Matching Regular Expression Matching LeetCode Solution** Problem Statement Regular Expression Matching Regular Expression Matching LeetCode Solution – Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*' where: '.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire input string (not partial). Example Test Case 1: Input: ...

**Question 47. 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 48. 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 49. 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 50. 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 51. Closest Leaf in a Binary Tree LeetCode Solution** Problem Statement Closest Leaf in a Binary Tree LeetCode Solution – Given the root of a binary tree where every node has a unique value and a target integer k, return the value of the nearest leaf node to the target k in the tree. Nearest to a leaf means the least number of edges traveled on the binary tree to ...

**Question 52. Excel Sheet Column Title LeetCode Solution** Problem Statement Excel Sheet Column Title LeetCode Solution – We are given a column number (let’s call it colNum) and need to return its corresponding column title as it appears in an excel sheet For example A -> 1 B -> 2 C -> 3 … Z -> 26 AA ...

**Question 53. Spiral Matrix LeetCode Solution** Problem Statement Spiral Matrix Problem says In Spiral Matrix we want to print all the elements of a matrix in a spiral form in the clockwise direction. Approach for Spiral Matrix: Idea The problem can be implemented by dividing the matrix into loops and printing all the elements in each ...

**Question 54. 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 55. Palindrome Linked List Leetcode Solution** In the problem “Palindrome Linked List”, we have to check whether a given singly integer linked list is a palindrome or not. Example List = {1 -> 2 -> 3 -> 2 -> 1} true Explanation #1: The list is palindrome as all elements from the start and back are ...

**Question 56. Contiguous Array** Given an array consisting of number 0’s and 1’s only. We have to find the length of the longest contiguous sub-array consisting o’s and 1’s equally. Example Input arr = [0,1,0,1,0,0,1] Output 6 Explanation The longest contiguous sub-array is marked in red [0,1,0,1,0,0,1] and its length is 6. Algorithm Set ...

**Question 57. 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 58. Merge Sort** What is merge sort? Merge Sort is a Recursive Procedure. It is also a divide and conquers algorithm. Now we need to know what divide and conquer algorithm is? It’s a type of procedure in which we divide the problem into subproblems and divide them until we find the shortest ...

**Question 59. Ugly Numbers** The positive numbers whose only prime factors are 2, 3, or 5 are known as ugly numbers. For eg- 8 is an ugly number because it’s an only prime factor is 2 but 7 is not an ugly number because it’s a prime factor is 7. 1 being an exception ...