797. All Paths From Source to Target Given a directed acyclic graph (DAG) of n nodes labeled from 0 to n - 1, find all possible paths from node 0 to node n - 1, and return them in any order. The graph is given as follows: graph[i] is a list of all nodes you can visit from node i (i.e., there is a directed edge from node i to node graph[i][j]). ...
207. Course Schedule There are a total of n courses you have to take labelled from 0 to n - 1. Some courses may have prerequisites, for example, if prerequisites[i] = [ai, bi] this means you must take the course bi before the course ai. Given the total number of courses numCourses and a list of the prerequisite pairs, return the ordering of courses you should take to finish all courses. ...
An a N x N grid composed of 1 x 1 squares, each 1 x 1 square consists of a /, , or blank space. These characters divide the square into contiguous regions. (Note that backslash characters are escaped, so a \ is represented as “\”.) Return the number of regions. Example 1: Input: [ " /", "/ " ] Output: 2 Explanation: The 2x2 grid is as follows: ...