P1546 [USACO3.1] 最短网络 Agri-Net

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#include<bits/stdc++.h>
using namespace std;const int N=110;
int n;
int g[N][N];
int st[N];
int dist[N];int prim()
{int res=0;memset(dist,0x3f,sizeof dist);for(int i=0;i<n;i++){int t=-1;for(int j=1;j<=n;j++){if(!st[j]&&(t==-1||dist[j]<dist[t])) t=j;}if(i) res+=dist[t];st[t]=true;for(int j=1;j<=n;j++){dist[j]=min(dist[j],g[t][j]);}}return res;}int main()
{ios::sync_with_stdio(0),cin.tie(0);cin>>n;for(int i=1;i<=n;i++){for(int j=1;j<=n;j++){cin>>g[i][j];}}cout<<prim()<<"\n";return 0;}