题解 | #【模板】最小生成树#

看了看题解区做法挺全的，我给一个vec存边的prim吧

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 5e5 + 5;
int __t = 1;
struct Edge {
    int u, v, w, idx;
    bool operator>(const Edge& other) const { return w > other.w; }
};
vector<Edge> adj[N];
int vis[N];
priority_queue<Edge, vector<Edge>, greater<Edge>> pq;
void solve() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({u, v, w, i});
        adj[v].push_back({v, u, w, i});
    }
    int sum = 0;
    vector<int> ed;
    pq.push({0, 1, 0, 0});
    while (!pq.empty()) {
        Edge e = pq.top();
        pq.pop();
        if (vis[e.v])
            continue;
        vis[e.v] = true;
        if (e.idx != 0) {
            sum += e.w;
            ed.push_back(e.idx);
        }
        for (auto next : adj[e.v]) {
            if (!vis[next.v]) {
                pq.push(next);
            }
        }
    }
    cout << sum << "\n";
    for (auto x : ed)
        cout << x << " ";
    cout << "\n";
}
int32_t main() {
#ifdef ONLINE_JUDGE
    ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    // cin >> __t;
    while (__t--)
        solve();
    return 0;
}