← All problems

797. All Paths from Source to Target

MediumOpen on LeetCodeProblem statement

Problem Statement

797. All Paths From Source to Target

Medium

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]).

 

Example 1:

Input: graph = [[1,2],[3],[3],[]]
Output: [[0,1,3],[0,2,3]]
Explanation: There are two paths: 0 -> 1 -> 3 and 0 -> 2 -> 3.

Example 2:

Input: graph = [[4,3,1],[3,2,4],[3],[4],[]]
Output: [[0,4],[0,3,4],[0,1,3,4],[0,1,2,3,4],[0,1,4]]

 

Constraints:

C++

Source file
class Solution {
public:
    vector<vector<int>> res;
    vector<int> v;
    void dfs(vector<vector<int>>& graph, int curr=0) {   //dfs
        v.push_back(curr);
        if(curr==graph.size()-1)
            res.push_back(v);
        else for(int nd: graph[curr])
            dfs(graph, nd);
        v.pop_back();
    }
    vector<vector<int>> allPathsSourceTarget(vector<vector<int>>& graph){
        dfs(graph);
        return res;
    }
};