POJ2421 Constructing Roads【最小生成树】

#include <cstdio>
#include <iostream>

using namespace std;
#define maxn 100+5
#define inf 0x3f3f3f3f

int maps[maxn][maxn];
bool vis[maxn];
int dis[maxn];
int n;

int Prim()
{
    for(int i=1;i<=n;i++)
        dis[i] = inf;
    int sum=0;
    dis[1] = 0;
    for(int i=1;i<=n;i++)
    {
        int tmp = inf,k=0;
        for(int j=1;j<=n;j++)
        {
            if(!vis[j]&&dis[j]<tmp)
            {
                tmp = dis[j];
                k=j;
            }
        }
        vis[k] = true;
        sum+=tmp;
        for(int i=1;i<=n;i++)
        {
            if(!vis[i]&&dis[i]>maps[k][i])
                dis[i] = maps[k][i];
        }
    }
    return sum;
}

int main()
{
    cin>>n;
    for(int i=1; i<=n; i++)
    {
       for(int j=1; j<=n; j++)
       {
           cin>>maps[i][j];
       }
    }
    int k;
    cin>>k;
    for(int i=0; i<k; i++)
    {
        int a,b;
        cin>>a>>b;
        maps[a][b]=maps[b][a] = 0;
    }
    cout<<Prim()<<endl;
    return 0;
}