Given a non-empty 2D array grid of 0’s and 1’s, an island is a group of 1’s (representing land) connected 4-directionally (horizontal or vertical.) Yo ...

Given a binary tree, count the number of uni-value subtrees. A Uni-value subtree means all nodes of the subtree have the same value. ExampleNo.1Input: ...

Given a binary tree, find the length of the longest path where each node in the path has the same value. This path may or may not pass through the roo ...

You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontally/ve ...

An image is represented by a 2-D array of integers, each integer representing the pixel value of the image (from 0 to 65535). Given a coordinate (sr, ...

You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need t ...

Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum. NoteA leaf is a node with no children. ExampleG ...

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. N ...

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path. ...

Given two integers n and k, return all possible combinations of k numbers out of 1 … n. ExampleInput: n = 4, k = 2 Output: 12345678[ [2,4], [3,4], ...