IBM is best known for **producing and selling computer hardware and software, as well as cloud computing and data analytics**. The company has also served as a major research and development corporation over the years, with significant inventions like the floppy disk, the hard disk drive, and the UPC barcode.

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

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

Categories of Questions

## IBM Array Questions

**Question 1. Minimum Swaps to Group All 1’s Together Leetcode Solution** Problem Statement Minimum Swaps to Group All 1’s Together Leetcode Solution – says that Given a binary array data, return the minimum number of swaps required to group all 1’s present in the array together in any place in the array. Input: data = [1,0,1,0,1] Output: 1 Explanation: There are 3 ways to group all ...

**Question 2. 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 3. k-th missing element in increasing sequence which is not present in a given sequence** The problem “k-th missing element in increasing sequence which is not present in a given sequence” states that you are given two arrays. One of them is arranged in ascending order and another normal unsorted array with number k. Find the kth missing element which is not present in normal ...

**Question 4. Maximum product of an increasing subsequence** Problem Statement The problem “Maximum product of an increasing subsequence” states that you are given an array of integers. Now you need to find out the maximum product you can achieve such that you multiply the elements of an increasing subsequence. The thing to note is that, we are not ...

**Question 5. Check in binary array the number represented by a subarray is odd or even** The problem “Check in binary array the number represented by a subarray is odd or even” states that you are given a binary array and a range. The array consists of the number in the form of 0s and 1s. The problem statement asks to find out the number represented ...

**Question 6. Distinct adjacent elements in an array** Problem Statement Suppose we have an integer array. The problem “Distinct adjacent elements in an array” asks to determine if it is possible to get the array in which all the adjacent numbers are distinct or not by swapping up two adjacent or neighbour elements in an array if it ...

**Question 7. Move all negative elements to end in order with extra space allowed** Problem Statement “Move all negative elements to end in order with extra space allowed” states that you are given an array containing positive and negative numbers both. The problem statement asks to move all the negative elements in the last of the array. Example arr[] = { 1,2,-3,-5,2,7,-9,-11 } 1, ...

**Question 8. Find all permuted rows of a given row in a matrix** Problem Statement Find all permuted rows of a given row in a matrix states that you are given a matrix of size m*n and a matrix row number says ‘row’. The problem statement asks to find out all the possible rows which are permutation to the given row. This is ...

**Question 9. Minimum number of subsets with distinct elements** Problem Statement Suppose you have an array of integers of size n. The problem statement asks to find out the minimum number of subsets with distinct elements, that is subsets that can be formed which contain all the different/distinct elements from the array. Example arr[] = {2,4,6,2,1,4,2} 3 Explanation: {1, ...

**Question 10. Maximum sum bitonic subarray** Problem Statement An array having n integers is given to us. We need to find the maximum sum bitonic subarray. A bitonic subarray is nothing but just a subarray where the elements are arranged in a specific order. Such that the first elements are in increasing order and then in ...

**Question 11. 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 12. 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 13. 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 14. Maximum Sum Increasing Subsequence** Problem Statement In the “Maximum Sum Increasing Subsequence” problem we have given an array. Find the sum of the maximum subsequence of the given array, that is the integers in the subsequence are in sorted order. A subsequence is a part of an array which is a sequence that is ...

**Question 15. 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 16. 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 17. 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 18. 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 19. 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 20. 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 21. 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 22. 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 ...

## IBM String Questions

**Question 23. Rearrange a binary string as alternate x and y occurrences** Problem Statement Suppose you are given a binary string, and two numbers x and y. The string consists of 0s and 1s only. The problem “Rearrange a binary string as alternate x and y occurrences” asks to rearrange the string such that the 0 comes x times ⇒ 1 comes ...

**Question 24. Group Words With Same Set of Characters** In Group words with same set of characters problem, we have given a list of words with lower cases. Implement a function to find all Words that have the same unique character set. Example Input Words[]={ “may”, “student”, “students”, “dog”,”studentssess”, “god”, “cat”, “act”,”tab”, “bat”, “flow”, “wolf”, “lambs”,”amy”, “yam”, “balms”, “looped”, ...

**Question 25. String Compression** In the String Compression problem, we have given an array a[ ] of type char. Compress it as the character and count of a particular character (if the count of character is 1 then the only character is stored in a compressed array). The length of the compressed array should ...

**Question 26. Valid Parentheses LeetCode Solution** In Valid Parentheses LeetCode problem we have given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid. Here we will provide a Valid Parentheses LeetCode Solution to you. An input string is valid if: Open brackets must be closed ...

## IBM Tree Questions

**Question 27. Check if the given array can represent Level Order Traversal of Binary Search Tree** Problem Statement The problem “Check if the given array can represent Level Order Traversal of Binary Search Tree” states that you are given a level order traversal of the binary search tree. And using the level order traversal of the tree. We need to efficiently find if the level order ...

## IBM Stack Questions

**Question 28. Sort a stack using recursion** Problem Statement The problem “Sort a stack using recursion” states that you are given a stack data structure. Sort its elements using recursion. Only the below-listed functions of the stack can be used – push(element) – to insert the element in the stack. pop() – pop() – to remove/delete the ...

**Question 29. Sorting array using Stacks** Problem statement The problem “Sorting array using Stacks” states that you are given a data structure array a[ ] of size n. Sort the elements of the given array using stack data structure. Example 2 30 -5 43 100 -5 2 30 43 100 Explanation: The elements are sorted in ...

**Question 30. Sort a stack using a temporary stack** Problem Statement The problem “Sort a stack using a temporary stack” states that you are given a stack data structure. Sort the elements of the given stack using a temporary stack. Example 9 4 2 -1 6 20 20 9 6 4 2 -1 2 1 4 3 6 5 ...

## IBM Queue Questions

**Question 31. Check if the given array can represent Level Order Traversal of Binary Search Tree** Problem Statement The problem “Check if the given array can represent Level Order Traversal of Binary Search Tree” states that you are given a level order traversal of the binary search tree. And using the level order traversal of the tree. We need to efficiently find if the level order ...

## IBM Matrix Questions

**Question 32. Find all permuted rows of a given row in a matrix** Problem Statement Find all permuted rows of a given row in a matrix states that you are given a matrix of size m*n and a matrix row number says ‘row’. The problem statement asks to find out all the possible rows which are permutation to the given row. This is ...

**Question 33. 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 34. 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 ...

## IBM Other Questions

**Question 35. Candy LeetCode Solution** Problem Statement: Candy LeetCode Solution: There are n children standing in a line. Each child is assigned a rating value given in the integer array ratings. You are giving candies to these children subjected to the following requirements: Each child must have at least one candy. Children with a higher rating get more ...

**Question 36. 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 37. 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 38. 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 39. String Compression LeetCode Solution** Problem Statement String Compression LeetCode Solution – Given an array of characters chars, compress it using the following algorithm: Begin with an empty string s. For each group of consecutive repeating characters in chars: If the group’s length is 1, append the character to s. Otherwise, append the character followed by the group’s length. The compressed string ...

**Question 40. Move Zeroes LeetCode Solution** Problem Statement The problem, Move Zeroes LeetCode Solution states that you are given an array containing zero and non-zero elements and you need to move all the zeroes to the end of the array, maintaining the relative order of non-zero elements in the array. You also need to implement an in-place ...

**Question 41. Search in a Binary Search Tree Leetcode Solution** In this problem, we are given a Binary Search Tree and an integer. We need to find the address of a node with value same as the given integer. As a check, we need to print the preorder traversal of the sub-tree that has this node as root. If there ...

**Question 42. Merge Two Sorted Lists Leetcode Solutions** Linked lists are quite like arrays in their linear properties. We can merge two sorted arrays to form an overall sorted array. In this problem, we have to merge two sorted linked lists in place to return a new list which contains elements of both lists in a sorted fashion. Example ...

**Question 43. Merge Two Sorted Linked Lists** In merge two sorted linked lists we have given head pointer of two linked lists, merge them such that a single linked list is obtained which has nodes with values in sorted order. return the head pointer of the merged linked list. Note: merge the linked list in-place without using ...

**Question 44. Sliding Window Maximum** In Sliding Window Maximum problem we have given an array nums, for each contiguous window of size k, find the maximum element in the window. Example Input nums[] = {1,3,-1,-3,5,3,6,7} k = 3 Output {3,3,5,5,6,7} Explanation Naive Approach for Sliding Window Maximum For every contiguous window of size k, traverse ...

**Question 45. Merge Two Sorted Lists Leetcode** What is merge two sorted lists problem on leetcode? This is so interesting question asked so many times in compnies like Amazon, Oracle, Microsoft, etc. In this problem(Merge Two Sorted Lists Leetcode), we have given two linked lists. Both linked lists are in increasing order. Merge both linked list in ...