N - 畅通工程再续

N - 畅通工程再续

思路：zz

#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define MAXN 310
using namespace std;
double ans;
int fa[MAXN];
int t,n,tot,sum;
double x[MAXN],y[MAXN];
struct nond{
    int x,y;double z;
}v[MAXN*MAXN];
int cmp(nond a,nond b){
    return a.z<b.z;
}
int find(int x){
    if(fa[x]==x)    return x;
    else  return fa[x]=find(fa[x]);
}
int main(){
    scanf("%d",&t);
    while(t--){
        scanf("%d",&n);
        for(int i=;i<=n;i++)    scanf("%lf%lf",&x[i],&y[i]);
        for(int i=;i<=n;i++)
            for(int j=i+;j<=n;j++){
                double tmp=sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));
                if(tmp>=&&tmp<=){ v[++tot].x=i;v[tot].y=j;v[tot].z=tmp; }
            }
        for(int i=;i<=n;i++)    fa[i]=i;
        sort(v+,v++tot,cmp);
        for(int i=;i<=tot;i++){
            int dx=find(v[i].x);
            int dy=find(v[i].y);
            if(dx==dy)    continue;
            fa[dy]=dx;sum++;
            ans+=v[i].z;
            if(sum==n-)    break;
        }
        if(sum<n-)    cout<<"oh!"<<endl;
        else    printf("%.1lf\n",ans*);
        ans=;tot=;sum=;
    }
}