畅通工程再续

#include<iostream>
#include<cstring>
#include<cmath>
#include<cstdio>

using namespace std;

#define N 110
#define INF 0xfffffff

struct node
{
    int x, y;
} P[N];

int vis[N];
double maps[N][N], dist[N];

void init()
{
    for(int i = 0; i < N; i++)
    {
vis[i] = 0;
        for(int j = 0; j < N; j++)
        {
            maps[i][j] = maps[j][i] = INF;
        }
    }
}
double prim(int n)
{
    vis[0] = 1;
    dist[0] = 0;
    int cou = 1;
    double ans = 0;

    for(int i = 0; i < n; i++)
        dist[i] = maps[0][i];

    for(int i = 0; i < n; i++)
    {
        int index, f;
        double Min = INF;
        index = f = 0;
        for(int j = 0; j < n; j++)
        {
            if(!vis[j] && dist[j] < Min)
                Min = dist[j], index = j, f = 1;   // 如果边权值满足题意，并且该点没有连接的话，f置为1，就把该值用上联通该点
        }
        if(f)
        {
            cou++;    //  cou计算已经被连接的点数，加一次边权值，联通点数加一
            vis[index] = 1;
            ans += Min;
        }


        for(int j = 0; j < n; j++)
        {
            if(!vis[j] && dist[j] > maps[j][index])
                dist[j] = maps[j][index];  // 最短路
        }
    }
    if(cou != n)
        return -1; 
    return ans;
}
int main()
{
    int t, c;

    cin >> t;

    while(t--)
    {
        cin >> c;

        init();

        for(int i = 0; i < c; i++)
            cin >> P[i].x >> P[i].y;

        for(int i = 0; i < c; i++)
        {
            for(int j = 0; j < c; j++)
            {
                int xx = P[i].x-P[j].x, yy = P[i].y-P[j].y;
                double q = sqrt(xx*xx+yy*yy);
                if(q >= 10 && q <= 1000)
                    maps[i][j] = maps[j][i] = q;  // 边权值即两点距离满足题意，就可以用，不然边权值就是INF，已初始化
            }
        }

        double ans = prim(c); 

        if(ans == -1)
            cout << "oh!" << endl;
        else
            printf("%.1f\n", ans*100);
    }
    return 0;
}