1053 Path of Equal Weight (30分) ♡

#include <iostream>
#include <cstring>
#include <vector>
#include <algorithm>

using namespace std;

const int N = 110;

int n, m, S;
int w[N];
bool g[N][N];
vector<vector<int>> ans;  //多维vector，相当于二维数组

void dfs(int u, int s, vector<int> &path)  //u表示当前搜到了第几个点
											//s表示当前总和
{
    bool is_leaf = true;     
    for (int i = 0; i < n; i ++ )		//判断是否是叶子节点
        if (g[u][i])
        {
            is_leaf = false; 
            break;
        }

    if (is_leaf)
    {
        if (s == S) ans.push_back(path);	 //如果答案是目标值，在答案中加入路径
    }
    else ///不是叶子节点
    {
        for (int i = 0; i < n; i ++ )   
            if (g[u][i])    
            {
                path.push_back(w[i]);  //搜索之前加入i的权值
                dfs(i, s + w[i], path);    
                path.pop_back();    //搜完之后恢复现场
            }
    }
}

int main()
{
    cin >> n >> m >> S;
    for (int i = 0; i < n; i ++ ) cin >> w[i];

    while (m -- ) //读入每条表
    {
        int id, k;
        cin >> id >> k;
        while (k -- )  //读入每个儿子
        {
            int son;
            cin >> son;
            g[id][son] = true;
        }
    }

    vector<int> path({w[0]});   //path初始化
    dfs(0, w[0], path);   //从根节点开始暴搜

    sort(ans.begin(), ans.end(), greater<vector<int>>()); //答案排序（从大到小

    for (auto p : ans)  //输出所有路径
    {
        cout << p[0];  //p是一个vector
        for (int i = 1; i < p.size(); i ++ ) cout << ' ' << p[i];
        cout << endl;
    }

    return 0;
}