HDU - 1875 最小生成树

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue>
#include <cmath>
#include <cstring>
using namespace std;
int fa[1000];
typedef pair<int, int> p;
struct edge
{
     int come, to;
     double d;
     bool operator <(const edge &p1)
     {
         return d < p1.d;
     }
}d[3000];
p pp[5000];
vector<edge> q;
int getf(int x)
{
    if(x == fa[x])
        return x;
    return fa[x] = getf(fa[x]);
}
void init()
{
    for(int i = 0; i < 1000; i++)
        fa[i] = i;
    q.clear();
    memset(pp, 0, sizeof(pp));
}
void Union(int x, int y)
{
    x = getf(x);
    y = getf(y);
    if(x == y)
        return;
    fa[x] = y;
}
double dis(p p1, p p2)
{
    return sqrt((p1.first - p2.first) * (p1.first - p2.first) + (p1.second - p2.second) * (p1.second - p2.second));

}
bool OK(int n)
{
    int father = getf(1);
    for(int i = 2; i <= n; i++)
        if(father != getf(i))
            return 0;
    return 1;
}
int main()
{
    int T;
    cin >> T;
    while(T--)
    {
        int n;
        cin >> n;
        init();
        for(int i = 1; i <= n; i++)
            cin >> pp[i].first >> pp[i].second;
        for(int i = 1; i < n; i++)
        {
            for(int j = i + 1; j <= n; j++)
            {
                double d = dis(pp[i], pp[j]);
                if(d >= 10 && d <= 1000.0)
                {
                    edge s;
                    s.come = i;
                    s.to = j;
                    s.d = d;
                    q.push_back(s);
                }
            }
        }
        sort(q.begin(), q.end());
        double sum = 0;
        for(int i = 0; i < q.size(); i++)
        {
            if(getf(q[i].come) != getf( q[i].to))
            {
                sum += q[i].d;
                Union(q[i].come, q[i].to);
            }
        }
        if(OK(n))
            printf("%.1lf\n", sum * 100);
        else
            printf("oh!\n");


    }
    return 0;
}