畅通工程再续

#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
int pre[10000],x[10000],y[10000];
struct inf{
    int u,v;
    double x;
}a[10000];
int cmp(inf a,inf b){
    return a.x<b.x;
}
double f(int x1,int x2, int y1, int y2){
    return sqrt((double)((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
}
int find(int i){
    return pre[i] == i?pre[i] : find(pre[i]);
}
int main(){
    int T;
    scanf("%d", &T);
    while(T--){
            int k,i,j,num = 1,sum = 0;
    double ans = 0;
    scanf("%d", &k);
    for(int i =1; i <= k; i++){
            scanf("%d%d", &x[i],&y[i]);
    }
    for(int i =1; i < k; i++){
            for(j = i+1;j <=k;j++){
                    double temp;
            temp = f(x[i],x[j],y[i],y[j]);
            if(temp>= 10.0&&temp<=1000.0){
                    a[num].u = i;
                    a[num].v = j;
                    a[num].x = temp;
                    num++;
            }
        }
    }
        for(int i =1; i <=num;i++)
                pre[i] = i;
        sort(a+1,a+num,cmp);
        for(int i = 1;i <num;i++){
                int x = find(a[i].u);
                int y = find(a[i].v);
                if(x!=y){
                        sum++;
                pre[x] = y;
                ans +=a[i].x;
                }
        }
        if(sum == k -1)
            printf("%.1lf\n",ans*100);
        else printf("oh!\n");
    }
    return 0;
}