原题链接：Leetcode 797. 所有可能的路径

class Solution {
public:
    vector<vector<int>> res;
    void dfs(vector<vector<int>>& g,int x,vector<int>& tmp)
    {
        if(x==0) 
        {
            vector<int> r(tmp);
            reverse(r.begin(),r.end());
            res.push_back(r);
        }
        for(auto num:g[x])
        {
            tmp.push_back(num);
            dfs(g,num,tmp);
            tmp.pop_back();
        }
    }
    vector<vector<int>> allPathsSourceTarget(vector<vector<int>>& graph) {
        int n=graph.size();
        vector<vector<int>> g(n);
        for(int i=0;i<n;i++)
        {
            for(auto x:graph[i]) g[x].push_back(i);
        }
        vector<int> tmp;
        tmp.push_back(n-1);
        dfs(g,n-1,tmp);
        return res;
    }
};

class Solution {
public:
    vector<vector<int>> res;
    vector<int> tmp;
    void dfs(vector<vector<int>>& graph,int x,int n)
    {
        if(x==n) res.push_back(tmp);
        for(auto num:graph[x])
        {
            tmp.push_back(num);
            dfs(graph,num,n);
            tmp.pop_back();
        }
    }
    vector<vector<int>> allPathsSourceTarget(vector<vector<int>>& graph) {
        int n=graph.size();
        tmp.push_back(0);
        dfs(graph,0,n-1);
        return res;
    }
};