Problem Statement Diagonal Traverse LeetCode Solution – Given an m x n matrix mat, return an array of all the elements of the array in a diagonal order. Input: mat = [[1,2,3],[4,5,6],[7,8,9]] Output: [1,2,4,7,5,3,6,8,9] Explanation Consider the indices of the diagonals of an NxM matrix. Let’s use a 4×4 matrix as an example: …
Problem Statement The Partition to K Equal Sum Subsets LeetCode Solution – “Partition to K Equal Sum Subsets” states that you’re given the integer array nums and an integer k, return true if it is possible to have k non-empty subsets whose sums are all equal. Example: Input: nums = [4,3,2,3,5,2,1], k = 4 Output: …
Problem Statement : Number of Closed Islands Leetcode Solution – Given a 2D grid consisting of 0s (land) and 1s (water). An island is a maximal 4-directionally connected group of 0s and a closed island is an island totally (all left, top, right, bottom) surrounded by 1s. Return the number of closed islands. Example : Example 1 Input: grid = [[1,1,1,1,1,1,1,0],[1,0,0,0,0,1,1,0],[1,0,1,0,1,1,1,0],[1,0,0,0,0,1,0,1],[1,1,1,1,1,1,1,0]] Output: 2 Explanation: Islands in gray …
Problem Statement Robot Bounded In Circle LeetCode Solution – On an infinite plane, a robot initially stands at (0, 0) and faces north. Note that: The north direction is the positive direction of the y-axis. The south direction is the negative direction of the y-axis. The east direction is the positive direction of the x-axis. The west direction is the …
Problem Statement Minimum Knight Moves LeetCode Solution – In an infinite chessboard with coordinates from -infinity to +infinity, you have a knight at square [0, 0]. A knight has 8 possible moves it can make, as illustrated below. Each move is two squares in a cardinal direction, then one square in an orthogonal direction. Return the minimum number …
Problem Statement Find the Duplicate Number LeetCode Solution – Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. There is only one repeated number in nums, return this repeated number. You must solve the problem without modifying the array nums and uses only constant extra space. Input: nums = [1,3,4,2,2] Output: 2 Explanation …
Problem Statement Snakes and Ladders LeetCode Solution – You are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style starting from the bottom left of the board (i.e. board[n – 1][0]) and alternating directions in each row. You start on the square 1 of the board. In each move, …
Problem Statement: Missing Element in Sorted Array LeetCode Solution – Given an integer array nums which are sorted in ascending order and all of its elements are unique and given also an integer k, return the kth missing number starting from the leftmost number of the array. Example: Example 1 Input: nums = [4,7,9,10], k = …
Problem Statement : Path Sum II LeetCode Solution – Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. Each path should be returned as a list of the node values, not node references. A root-to-leaf path is a path starting from …
Problem Statement Flatten 2D Vector LeetCode Solution – Design an iterator to flatten a 2D vector. It should support the next and hasNext operations. Implement the Vector2D class: Vector2D(int[][] vec) initializes the object with the 2D vector vec. next() returns the next element from the 2D vector and moves the pointer one step forward. You may assume that all …