# Infosys Interview Questions

Infosys Limited is an Indian multinational information technology company that provides business consultinginformation technology and outsourcing services. The company was founded in Pune and is headquartered in Bangalore. Infosys is the second-largest Indian IT company after Tata Consultancy Services by 2020 revenue figures and the 602nd largest public company in the world, according to the Forbes Global 2000 ranking.

It has got a 3.9* rating on Glassdoor and is considered one of the best service-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 Infosys Interview Experience for the interview. We have collected past frequently asked questions from Infosys Interview Experience for your reference.

## Infosys Array Questions

Question 1. Most Frequent Element in an Array You are given an array of integers. The problem statement says that you have to find out the most frequent element present in an array. If there are multiple values that occurs the maximum number of times, then we have to print any of them. Example Input [1, 4,5,3,1,4,16] Output ...

Question 2. 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 3. 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[] = ...

## Infosys String Questions

Question 4. Score of Parenthesis LeetCode Solution Problem Statement The score of Parenthesis LeetCode Solution says – Given a balanced parentheses string s and return the maximum score. The score of a balanced parenthesis string is based on the following rules: "()" has score 1. AB has score A + B, where A and B are balanced parenthesis strings. (A) has score 2 * A, where A is a ...

Question 5. Reverse a String Problem Statement “Reverse a String” problem states that you are given a string s of size n. Write a program to reverse it. So, what does reversing a string means? It generally means reversing the input string that we are given. That is it is defined as an operation doing ...

Question 6. Valid Palindrome Given a string s of length n. Write a program to find if the string is valid palindrome or not. If not you may delete at most one character from the string to make it a palindrome. Any string which is the same as it’s reverse is known as a ...

Question 7. Palindrome using Recursion Problem Statement In the “Recursive Palindrome Check” or “Palindrome using Recursion” problem we have given a string “s”. We have to write a program to check if the given string is palindrome or not using recursion. A palindrome is a word, number, phrase, or other sequence of characters that reads ...

Question 8. Remove Extra Spaces from a String Problem Statement In the “Remove Extra Spaces from a String” problem we have given a string “s”. Write a program to remove all extra_spaces from the given string. Input Format The first and only one line containing a string s with some spaces. Output Format Print a string after removing ...

## Infosys Tree Questions

Question 9. Binary Search Tree A binary search tree is a Binary tree with some rules that allows us to maintain the data in a sorted fashion. As it is a binary tree hence, a node can have at max 2 children. Structure of a Binary Search Tree node   Rules for Binary tree to ...

Question 10. Binary Tree Data Structure In this article, we will read about the Binary Tree Data Structure. Trees are hierarchical data structures where every node has a parent node except the root node. The nodes with no child are called leaves. Need for Trees? 1. Trees are used when we need to store data in ...

Question 11. Types of Binary Tree Before we proceed, we first know what BT really is? Binary Tree is a type of data structure that is hierarchical in nature. A BT is represented by nodes where every node has left, a right pointer, and data as the weight of node. Each node can contain a maximum ...

Question 12. BFS vs DFS for Binary Tree Breadth First Search (BFS) Do we already know about what actually BFS is? if not then don’t need to feel bad just read the whole article and visit our previous article on Breadth First Search for better understanding. BFS is a level order traversal in which we visit the nodes of ...

## Infosys Graph Questions

Question 13. Depth First Search (DFS) for a Graph Depth First Search is a traversing or searching algorithm in tree/graph data structure. The concept of backtracking we use to find out the DFS. It starts at a given vertex (any arbitrary vertex) and explores it and visit the any of one which is connected to the current vertex and start ...

Question 14. Graph and its representation A graph is an abstract data type representing relations or connections between objects(like cities are connected by rough road). In the graph and its representation, basically, the relation is denoted by edges and objects by vertices(nodes). A graph consists of a finite set of vertices and edges. A graph is ...

## Infosys Stack Questions

Question 15. Score of Parenthesis LeetCode Solution Problem Statement The score of Parenthesis LeetCode Solution says – Given a balanced parentheses string s and return the maximum score. The score of a balanced parenthesis string is based on the following rules: "()" has score 1. AB has score A + B, where A and B are balanced parenthesis strings. (A) has score 2 * A, where A is a ...

Question 16. Reverse a stack without using extra space in O(n) Problem Statement The problem “Reverse a stack without using extra space in O(n)” states that you are given a stack data structure. Reverse the given stack without using extra O(n) space. Example 5 4 3 2 1 1 2 3 4 5 80 60 10 20 20 10 60 80 ...

Question 17. Implement a stack using single queue Problem Statement The problem “Implement a stack using single queue” asks us to implement a stack (LIFO) data structure using a queue (FIFO) data structure. Here LIFO means Last In First Out while FIFO means First In First Out. Example push(10) push(20) top() pop() push(30) pop() top() Top : 20 ...

Question 18. Tracking current Maximum Element in a Stack Problem Statement “Tracking current Maximum Element in a Stack” states that you are given a stack data structure. Create a function to keep the track of the maximum value in the stack till the current index. Example 4 19 7 14 20 4 19 19 19 20 Explanation: The maximum ...

Question 19. Recursion What is Recursion? Recursion is simply defined as a function calling itself. It uses its previously solved sub-problems to compute a bigger problem. It is one of the most important and tricky concepts in programming but we can understand it easily if we try to relate recursion with some real ...

## Infosys Queue Questions

Question 20. Implement a stack using single queue Problem Statement The problem “Implement a stack using single queue” asks us to implement a stack (LIFO) data structure using a queue (FIFO) data structure. Here LIFO means Last In First Out while FIFO means First In First Out. Example push(10) push(20) top() pop() push(30) pop() top() Top : 20 ...

Question 21. Priority Queue in C++ FIFO manner is used to implement a queue. In a queue, insertions are done at one end (rear) and deletion takes place at another end (front). Basically, the element enters first is deleted first. We implement a priority queue using c++ inbuilt functions. Characteristics of Priority Queue A priority queue ...

Question 22. Circular Queue A circular queue is an advanced form of a linear queue. In the linear queue, we can’t insert an element in the queue if the rear is pointing to the last index of the queue and the queue is not completely filled. This causes wastage of memory. To overcome this ...

## Infosys Other Questions

Question 23. 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 24. Binary Search LeetCode Solution Problem Statement Binary Search LeetCode Solution says that – Given an array of integers nums which is sorted in ascending order, and an integer target, write a function to search target in nums. If target exists, then return its index. Otherwise, return -1. You must write an algorithm with O(log n) runtime complexity. Example 1: Input: nums = [-1,0,3,5,9,12], target ...

Question 25. 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 26. Reverse Integer Leetcode Solution Problem Statement Reverse Integer LeetCode Solution says that – Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0. Assume the environment does not allow you to store 64-bit integers (signed or unsigned). Example 1: ...

Question 27. Palindrome Number LeetCode Solution Problem Statement Palindrome Number LeetCode Solution says that – Given an integer x, return true if x is palindrome integer. An integer is a palindrome when it reads the same backward as forward. For example, 121 is a palindrome while 123 is not.   Example 1: Input: x = 121 Output: true Explanation: 121 reads as 121 from left to right ...

Question 28. 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 29. Fibonacci Number LeetCode Solution Problem Statement Fibonacci Number LeetCode Solution – “Fibonacci Number” states that The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that each number is the sum of the two preceding ones, starting from 0 and 1. That is, F(0) = 0, F(1) = 1 F(n) = F(n - 1) + F(n ...

Question 30. 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 31. Top K Frequent Words In top K frequent words problem, we have given a list of words and an integer k. Print k most frequently used strings in the list. Example Input : list = {“code”, “sky”, “pen”, “sky”, “sky”, “blue”, “code”} k = 2 Output :  sky code Input : list = {“yes”, ...

Question 32. OSI Model This model was developed in 1983 by the International Standards Organization (ISO). This was the first step taken to standardized the international protocols used in various layers. As it deals with connecting open systems, that is, systems that are open for communication with other systems, the model is called the ...

Question 33. Fibonacci numbers Fibonacci numbers are the numbers that form the series called Fibonacci series and are represented as Fn. The first two Fibonacci numbers are 0 and 1 respectively i.e. F0=0 and F1=1. Starting from the third Fibonacci number each Fibonacci number is the sum of its previous two numbers in the ...

Question 34. Dynamic Programming Basics In Dynamic Programming basics, we will cover the basics of DP and its differences from the Greedy method, Divide and Conquer and Recursion. Dynamic programming is an approach just like recursion and divide and conquer. It divides the problem into subproblems. But instead of solving these subproblems independently like divide ...

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