Problem Statement Isomorphic Strings LeetCode Solution – Given two strings s and t, determine if they are isomorphic. Two strings s and t are isomorphic if the characters in s can be replaced to get t. All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the …
Problem Statement Peak Index in a Mountain Array LeetCode Solution – An array arr a mountain if the following properties hold: arr.length >= 3 There exists some i with 0 < i < arr.length – 1 such that: arr[0] < arr[1] < … < arr[i – 1] < arr[i] arr[i] > arr[i + 1] > … > …
Problem Statement: Swim in Rising Water LeetCode Solution : You are given an n x n integer matrix grid where each value grid[i][j] represents the elevation at that point (i, j). The rain starts to fall. At time t, the depth of the water everywhere is t. You can swim from a square to another 4-directionally adjacent square if …
Unique Binary Search Trees LeetCode Solution says that – Given an integer n, return the number of structurally unique BST’s (binary search trees) which has exactly n nodes of unique values from 1 to n. Example 1: Input: n = 3 Output: 5 Example 2: Input: n = 1 Output: 1 Constraints: 1 <= n <= 19 …
Problem Statement: Insert Delete GetRandom O(1) – Duplicates allowed LeetCode Solution: RandomizedCollection is a data structure that contains a collection of numbers, possibly duplicates (i.e., a multiset). It should support inserting and removing specific elements and also removing a random element. Implement the RandomizedCollection class: RandomizedCollection() Initializes the empty RandomizedCollection object. bool insert(int val) Inserts an item val into …
Problem Statement: H-Index Leetcode solution says that – Given an array of integers “citations” where citations[i] is the number of citations a researcher received for their ith paper, return researcher’s H-Index. If several H-Index values are present, return the maximum among them. Definition of H-Index: A scientist has an index …
Range Sum of BST LeetCode Solution says that – Given the root the node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high]. Example 1: Input: root = [10,5,15,3,7,null,18], low = 7, high = 15 Output: 32 Explanation: …
Problem Statement: Step-By-Step Directions From a Binary Tree Node to Another LeetCode Solution – You are given the root of a binary tree with n nodes. Each node is uniquely assigned a value from 1 to n. You are also given an integer startValue representing the value of the start node s, and a different integer destValue representing the value of the destination …
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: …
Problem Statement Rotate String LeetCode Solution – Given two strings s and goal, return true if and only if s can become goal after some number of shifts on s. A shift on s consists of moving the leftmost character of s to the rightmost position. For example, if s = “abcde”, then it will …