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] …
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 …
Construct Complete Binary Tree from its Linked List Representation
Given the linked list representation of a complete binary tree. The linked list is in the order of level order traversal of the tree. Write an algorithm to construct the complete binary tree back from its linked list representation. Example Input 1 -> 2 -> 3 -> 4 -> 5 …
Lowest Common Ancestor
Given the root of a binary tree and two nodes n1 and n2, find the LCA(Lowest Common Ancestor) of the nodes. Example What is Lowest Common Ancestor(LCA)? The ancestors of a node n are the nodes present in the path between root and node. Consider the binary tree shown in …
Longest Palindromic Subsequence
In the longest palindromic subsequence problem we have given a string, find the length of the longest palindromic subsequence. Examples Input: TUTORIALCUP Output: 3 Input: DYNAMICPROGRAMMING Output: 7 Naive Approach for Longest Palindromic Subsequence The naive approach to solve the above problem is to generate all the subsequences of the …
Find The Duplicate Number
Given an array nums containing (n + 1) elements and every element is between 1 to n. If there is only one duplicate element, find the duplicate number. Examples Input: nums = {1, 3, 4, 2, 2} Output: 2 Input: nums = {3, 1, 3, 4, 2} Output: 3 Naive …
Reservoir Sampling
Reservoir Sampling is a technique of selecting k reservoir items randomly from a given list of n items, where n is very large. For example, search lists in Google, YouTube etc. Naive Approach for Reservoir Sampling Build a reservoir array of size k, randomly select items from the given list. …
Split Array Into Consecutive Subsequences
Given a sorted array(in ascending order), check if the array can be split into 1 or more subsequences of length greater than equals to 3 such that every subsequence contains consecutive numbers. Examples Input: arr[] = {1,2,3,3,4,5} Output: true Explanation: The array can be split into 2 subsequences as, sub1[] …
Evaluate Division
In evaluate division problem we have given some equations, in the form, A/B = k, where A and B are strings and k is a real number. Answer some queries, if the answer does not exist return -1. Example Input: equations: a/b = 2.0 and b/c = 3.0 queries: a/c …