poj 1258 Agri-Net

简单的模板题：prim算法适合浓密图：

#include<stdio.h>
#include<string.h>
#define MAXN 110
#define INF 100000000

int n, v[MAXN], low[MAXN], w[MAXN][MAXN];

void solve()
{
        int ans = 0;
        memset(v,0,sizeof(v));
        v[0] = 1;
        for(int i = 1; i < n; i ++) low[i] = w[0][i];
        for(int i = 0; i < n-1; i ++)
        {
            int min = INF, p;
            for(int j = 0; j < n; j ++)
                if(!v[j] && low[j] < min) min = low[j], p = j;
            v[p] = 1;
            ans += min;
            for(int j = 0; j < n; j ++)
                if(!v[j] && low[j] > w[p][j]) low[j] = w[p][j];
        }
        printf("%d\n",ans);
}

int main()
{
    while(~scanf("%d",&n))
    {
        for(int i = 0; i < n; i ++)
            for(int j = 0; j < n; j ++)
            {
                int a;
                scanf("%d",&a);
                w[i][j] = a;
            }
            solve();
    }
    return 0;
}