c++堆优化Prim

#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> PII;
#define fi first
#define se second

const int N=105;
int n;
int g[N][N];
bool vis[N];
int dist[N];

int prim(){
    priority_queue<PII, vector<PII>, greater<PII>> q;
    int ans=0;
    dist[1]=0;
    q.push({dist[1], 1});
    while(!q.empty()){
        int node=q.top().se;
        q.pop();
        if(vis[node]) continue;
        vis[node]=true;
        ans+=dist[node];
        for(int i=1; i<=n; ++i){
            if(dist[i]>g[node][i]){
                dist[i]=g[node][i];
                q.push({dist[i], i});
            }
        }
    }
    return ans;
}

int main(){
    memset(vis, 0x00, sizeof vis);
    memset(dist, 0x3f, sizeof dist);
    cin>>n;
    for(int i=1; i<=n; ++i)
        for(int j=1; j<=n; ++j)
            cin>>g[i][j];

    cout<<prim()<<endl;

    return 0;
}