UVA 10369 - Arctic Network

来源：互联网发布：洗车哪个软件好编辑：程序博客网时间：2024/05/18 06:04

最小生成树问题，kruskal算法的变形。

代码如下：

#include<stdio.h>#include<math.h>#include<stdlib.h>#define MAXN1 500+10#define MAXN 3000000int z, n, s, m, x[MAXN1], y[MAXN1], u[MAXN], v[MAXN], p[MAXN1], r[MAXN];double w[MAXN], flag[MAXN];int cmp(const void *_p, const void *_q){    int *p = (int *)_p;    int *q = (int *)_q;    return w[*p] > w[*q] ? 1: -1;}int find(int o) {return p[o] == o ? o : p[o] = find(p[o]);}double kruskal(){    int q = 0;    for(int i = 0; i <= m; i ++) p[i] = i;    for(int i = 0; i <= z; i ++) r[i] = i;    qsort(r, z, sizeof(r[0]), cmp);    for(int i = 0; i < z; i ++)    {        int e = r[i]; int x1 = find(u[e]); int y1 = find(v[e]);        if(x1 != y1) { p[x1] = y1;flag[q++] = w[e];}    }    return flag[q-s];}void init(){    while(~scanf("%d",&n))        while(n --)        {            scanf("%d%d",&s,&m);            for(int i = 1; i <= m; i ++)                scanf("%d%d",&x[i],&y[i]);            z = 0;             for(int i = 1; i <= m; i ++)                for(int j = i+1; j <= m; j ++)                {                    u[z] = i; v[z] = j;                    w[z++] = sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));                }            printf("%.2lf\n",kruskal());        }}int main(){    init();    return 0;}

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