LeetCode-797. All Paths From Source to Target

Given a directed, acyclic graph of N nodes.  Find all possible paths from node 0 to node N-1, and return them in any order.

The graph is given as follows:  the nodes are 0, 1, ..., graph.length - 1.  graph[i] is a list of all nodes j for which the edge (i, j) exists.

Example:
Input: [[1,2], [3], [3], []] 
Output: [[0,1,3],[0,2,3]] 
Explanation: The graph looks like this:
0--->1
|    |
v    v
2--->3
There are two paths: 0 -> 1 -> 3 and 0 -> 2 -> 3.

Note:

• The number of nodes in the graph will be in the range [2, 15].
• You can print different paths in any order, but you should keep the order of nodes inside one path.

题解：

class Solution {
public:
    void dfs(vector<vector<int>>& graph, int k, int n, vector<int> &cur, vector<vector<int>> &res) {
        if (k == n) {
            res.push_back(cur);
        }
        else {
            for (int i = 0; i < graph[k].size(); i++) {
                cur.push_back(graph[k][i]);
                dfs(graph, graph[k][i], n, cur, res);
                cur.pop_back();
            }
        }
    }
    vector<vector<int>> allPathsSourceTarget(vector<vector<int>>& graph) {
        int n = graph.size();
        vector<vector<int>> res;
        vector<int> cur(1, 0);
        dfs(graph, 0, n - 1, cur, res);
        return res;
    }
};