图的存储 邻接表

#include<bits/stdc++.h>

using namespace std;

const int N = 1010;

struct edge 
{
    int v;
    int w;
};

vector<edge> e[N];//边集数组

void dfs(int u, int fa)
{
    for(auto ed : e[u])
    {
        int v = ed.v, w = ed.w;
        if(v == fa) continue;
        printf("%d %d %d\n", u, v, w);
        dfs(v, u);
    }
}

int n, m;
int a, b, c;
int main()
{
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= m; i++)
    {
        scanf("%d %d %d", &a, &b, &c);
        e[a].push_back({b, c});
        e[b].push_back({a, c});
    }

    dfs(1, 0);
    return 0;
}