UVA 10034 Freckles

MST直接上代码了

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <stack>
#include <queue>
#include <cctype>
#include <cstdio>
#include <string>
#include <vector>
#include <climits>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
#define LL long long
#define PI 3.1415926535897932626
using namespace std;
int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);}
#define MAXN 110
int p[MAXN],N,cas;
int Find(int x) {return p[x] == x ? x : p[x] = Find(p[x]);}
struct dis
{
    int u,v;
    double dist;
    friend bool operator < (const dis &a,const dis &b)
    {
        return a.dist < b.dist;
    }
}d[MAXN * MAXN];
struct node
{
    double x,y;
}src[MAXN];
void init()
{
    scanf("%d",&N);
    for (int i = 1; i <= N; i++) scanf("%lf%lf",&src[i].x,&src[i].y);
    cas = 0;
    for (int i = 1; i <= N; i++)
        for (int j = i + 1; j <= N; j++)
     {
        d[cas].u = i; d[cas].v = j;
        //printf("%lf %lf %lf %lf\n",src[i].x,src[j].x,src[i].y,src[j].y);
        d[cas++].dist = sqrt((src[j].x - src[i].x) * (src[j].x - src[i].x) + (src[j].y - src[i].y) * (src[j].y - src[i].y));
     }
    sort(d,d + cas);
}
double kruskal()
{
    double ans = 0;
    //for (int i = 0; i < cas; i++) printf("%d %d %2.lf\n",d[i].u,d[i].v,d[i].dist);
    for (int i = 0; i <= N; i++) p[i] = i;
    for (int i = 0; i < cas; i++)
    {
        int  u = d[i].u, v = d[i].v;
        double w = d[i].dist;
        //printf("%.2lf\n",w);
        int  x = Find(u) , y = Find(v);
        if (x != y)
        {
            //printf("%.2lf\n",w);
            ans += w;
            p[x] = y;
        }
    }
    return ans;
}
int main()
{
    int T;
    scanf("%d",&T);
    while (T--)
    {
        init();
        double ans = kruskal();
        printf("%.2f\n",ans);
        if (T) putchar('\n');
    }
    return 0;
}