We are given a 2-dimensional grid. “.” is an empty cell, “#” is a wall, “@” is the starting point, (“a”, “b”, …) are keys, and (“A”, “B”, …) are locks ...

An undirected, connected graph of N nodes (labeled 0, 1, 2, …, N-1) is given as graph. graph.length = N, and j != i is in the list graph[i] exactly on ...

We have a list of bus routes. Each routes[i] is a bus route that the i-th bus repeats forever. For example if routes[0] = [1, 5, 7], this means that t ...

There are n cities connected by m flights. Each fight starts from city u and arrives at v with a price w. Now given all the cities and flights, togeth ...

Given an undirected graph, return true if and only if it is bipartite. Recall that a graph is bipartite if we can split it’s set of nodes into two ind ...

Let’s play the minesweeper game! You are given a 2D char matrix representing the game board. ‘M’ represents an unrevealed mine, ‘E’ represents an unre ...

You have a lock in front of you with 4 circular wheels. Each wheel has 10 slots: ‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’. The wheels can rota ...

There are N network nodes, labelled 1 to N. Given times, a list of travel times as directed edges times[i] = (u, v, w), where u is the source node, v ...

You are given a data structure of employee information, which includes the employee’s unique id, his importance value and his direct subordinates’ id. ...

Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell. The distance between two adjacent cells is 1. ExampleNo.1Input: ...