30+ Supercoder Interview Questions and Answers

Q1. Optimal BST Problem Statement

You are given a sorted array representing keys of a BST and an array of frequency counts showing how often each key is searched. Your task is to construct a binary search tree (BST...read more

Q2. Stock Trading Maximum Profit Problem

Given the stock prices for 'N' days, your goal is to determine the maximum profit that can be achieved. You can buy and sell the stocks any number of times but can only hold...read more

Q3. Find The Repeating And Missing Number Problem Statement

You are provided with an array nums which contains the first N positive integers. In this array, one integer appears twice, and one integer is missing. Yo...read more

Q4. Optimal Strategy for a Coin Game

You are playing a coin game with your friend Ninjax. There are N coins placed in a straight line.

Here are the rules of the game:

1. Each coin has a value associated with it.
 2....read more

Q5. Number of Distinct Substrings Problem Statement

Given a string WORD containing lowercase English alphabets and having length N, determine the number of distinct substrings in WORD.

Input:

The first line include...read more

Q6. Counting Triangles in Graphs

Given two graphs – a directed graph DIR_GRAPH and an undirected graph UNDIR_GRAPH – you are tasked with counting the number of triangles in each of the graphs.

Example:

In the examp...read more

Q7. Find Distinct Palindromic Substrings

Given a string 'S', identify and print all distinct palindromic substrings within it. A palindrome reads the same forwards and backwards. For example, 'bccb' is a palindrome...read more

Q8. Distance Between Two Nodes in a Binary Tree

Given a binary tree and the values of two distinct nodes, determine the distance between these two nodes in the tree. The distance is defined as the minimum number of...read more

Q9. Bit Majority Number Generation

You are given an array arr consisting of N integers. Construct a number from these integers such that, for each bit position, if the quantity of set bits (1s) is greater than the ...read more

Q10. Shuffle Two Strings

You are provided with three strings: A, B, and C. Your task is to determine if C is formed by interleaving A and B. A string C is considered an interleaving of A and B if:

• The length of C i...read more

Q11. Stack with getMin Operation

Create a stack data structure that supports not only the usual push and pop operations but also getMin(), which retrieves the minimum element, all in O(1) time complexity without usi...read more

Q12. Ninja's Complement Problem Statement

Every day, Ninja dreams of a number but does not understand its significance. Upon investigation, Ninja discovers that converting this number to binary, taking its complemen...read more

Q13. Sum of Digits Problem Statement

Given an integer 'N', continue summing its digits until the result is a single-digit number. Your task is to determine the final value of 'N' after applying this operation iterat...read more

Q14. Count Ways to Reach the N-th Stair Problem Statement

You are provided with a number of stairs, and initially, you are located at the 0th stair. You need to reach the Nth stair, and you can climb one or two step...read more

Q15. Ninja and Sorted Array Merging Problem

Ninja is tasked with merging two given sorted integer arrays ARR1 and ARR2 of sizes 'M' and 'N', respectively, such that the merged result is a single sorted array within ...read more

Q16. Binary Tree to Doubly Linked List

Transform a given Binary Tree into a Doubly Linked List.

Ensure that the nodes in the Doubly Linked List follow the Inorder Traversal of the Binary Tree.

Input:

The first line ...read more

Q17. Validate Binary Search Tree (BST)

You are given a binary tree with 'N' integer nodes. Your task is to determine whether this binary tree is a Binary Search Tree (BST).

BST Definition:

A Binary Search Tree (BST)...read more

Q18. Word Distance Calculation

Given a document represented as an array/list ARR of words with length N, find the smallest distance between two given words for multiple queries. The distance is defined as the differ...read more

Q19. Decode Ways Problem Statement

Given a string strNum that represents a number, the task is to determine the number of ways to decode it using the following encoding: 'A' - 1, 'B' - 2, ..., 'Z' - 26.

Input:

The f...read more

Q20. Longest Palindromic Subsequence Problem Statement

Given a string A consisting of lowercase English letters, determine the length of the longest palindromic subsequence within A.

Explanation:

• A subsequence is d...read more

Q21. Serialize and Deserialize Binary Tree Problem Statement

Given a binary tree of integers, your task is to implement serialization and deserialization methods. You can choose any algorithm for serialization and d...read more

Q22. Level Order Traversal Problem Statement

Given a binary tree of integers, return the level order traversal of the binary tree.

Input:

The first line contains an integer 'T', representing the number of test cases...read more

Q23. Combination Sum Problem Statement

Given an array of distinct positive integers ARR and a non-negative integer 'B', find all unique combinations in the array where the sum is equal to 'B'. Numbers can be chosen ...read more

Q24. Palindrome Permutation - Problem Statement

Determine if a permutation of a given string S can form a palindrome.

Example:

Input:

string S = "aab"

Output:

"True"

Explanation:

The permutation "aba" of the string ...read more

Q25. Number of Islands Problem Statement

You are given a non-empty grid that consists of only 0s and 1s. Your task is to determine the number of islands in this grid.

An island is defined as a group of 1s (represent...read more

Q26. Generate All Parentheses Combinations

Given an integer N, your task is to create all possible valid parentheses configurations that are well-formed using N pairs. A sequence of parentheses is considered well-fo...read more