# American Express Interview Questions  ## Array Questions American Express

Question 1. Subarray Sum Equals k Given an integer array and an integer k. Find total number of contiguous subarrays of given array whose sum of elements is equal to k. Example   Input 1: arr[] = {5,0,5,10,3,2,-15,4} k = 5 Output: 7 Input 2: arr[] = {1,1,1,2,4,-2} k = 2 Output: 4 Explanation : consider example-1 ...

Question 2. 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 3. 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 ...

## String Questions American Express

Question 4. Convert a String that is Repetition of a Substring of Length K Problem Statement   In the “Convert a String that is Repetition of a Substring of Length K” problem we have given a string “s” and an integer “k”. Write a program to check whether is it possible to convert it to a string that is the repetition of a substring with ...

## Tree Questions American Express

Question 5. Check whether a given Binary Tree is Complete or not Problem Statement   The problem “Check whether a given Binary Tree is Complete or not” states that you are given the root of a binary tree, check whether the tree is complete or not. A complete Binary Tree has all its levels filled except for the last level and the nodes ...

Question 6. Convert a normal BST to Balanced BST Problem Statement   Given a Binary Search Tree(BST), write an algorithm to convert the BST to a Balanced Binary Search Tree. A balanced Binary Search tree is nothing but a binary search tree whose difference between the height of left subtree and right subtree is less than or equal to 1. ...

## Stack Questions American Express

Question 7. Check if a queue can be sorted into another queue using a stack Problem Statement   The problem “Check if a queue can be sorted into another queue using a stack” states that you are given a queue containing n elements, the elements in the queue are a permutation of numbers 1 to n. Check if this queue can be arranged in increasing order ...

## Queue Questions American Express

Question 8. Implementation of Deque using Doubly Linked List Problem Statement   The problem “Implementation of Deque using Doubly Linked List” states that you need to implement the following functions of Deque or Doubly Ended Queue using a doubly linked list, insertFront(x) : Add element x at the starting of Deque insertEnd(x) : Add element x at the end of ...

Question 9. Check whether a given Binary Tree is Complete or not Problem Statement   The problem “Check whether a given Binary Tree is Complete or not” states that you are given the root of a binary tree, check whether the tree is complete or not. A complete Binary Tree has all its levels filled except for the last level and the nodes ...

Question 10. Check if a queue can be sorted into another queue using a stack Problem Statement   The problem “Check if a queue can be sorted into another queue using a stack” states that you are given a queue containing n elements, the elements in the queue are a permutation of numbers 1 to n. Check if this queue can be arranged in increasing order ...

Question 11. Smallest Multiple of a Given Number In the smallest multiple of a given number made of digits 0 and 9 only problem we have given a number n, find the smallest number made from digits 0 and 9 that is divisible by n. Assume that the answer will not exceed 106. Examples   Input 3 Output 9 ...

## Other Questions American Express

Question 12. Find the point where a monotonically increasing function becomes positive first time Problem Statement   In the “Find the point where a monotonically increasing function becomes positive first time” we have given a function “int f(unsigned int x)” which takes a non-negative integer ‘x’ as input and returns an integer as output. The function is monotonically increasing with respect to the value of x, i.e., the ...