You are given a m x n 2D grid initialized with these three possible values. -1 - A wall or an obstacle. 0 - A gate. INF - Infinity means an empty roo ...

Given a 2D board containing ‘X’ and ‘O’ (the letter O), capture all regions surrounded by ‘X’. A region is captured by flipping all ‘O’s into ‘X’s in ...

Given an m x n matrix of non-negative integers representing the height of each unit cell in a continent, the “Pacific ocean” touches the left and top ...

One way to serialize a binary tree is to use pre-order traversal. When we encounter a non-null node, we record the node’s value. If it is a null node, ...

You need to find the largest value in each row of a binary tree. ExampleInput: 12345 1 / \ 3 2 / \ \ 5 3 9 Output: [1, 3, 9] Code1234 ...

Given a binary tree, find the leftmost value in the last row of the tree. ExampleNo.1Input: 123 2 / \1 3 Output:1 No.2Input: 1234567 1 / \ 2 ...

Given a binary tree, return the zigzag level order traversal of its nodes’ values. (ie, from left to right, then right to left for the next level and ...

You are given coins of different denominations and a total amount of money. Write a function to compute the number of combinations that make up that a ...

You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you nee ...

You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins. Given n, find the total number ...