UVA 10803 Thunder Mountain

 

大意：让你求一组城镇A与B之间的最大距离，不能大于10，如果有城镇不连通，则输出Send Kurdy。

思路：Floyd

CODE：

 

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <queue>
using namespace std;

#define MAXN 1100
#define INF 0X3F3F3F3F

struct node
{
    double x, y;
}a[MAXN];

int n, m;

double d[MAXN][MAXN];

double dist(node a, node b)
{
    double x1 = a.x, y1 = a.y;
    double x2 = b.x, y2 = b.y;
    return sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));
}

void init()
{
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= n; j++)
        {
            if(i == j) d[i][j] = 0;
            else d[i][j] = INF;
        }
    }
}

void Floyd()
{
    double ans = -1; 
    for(int k = 1; k <= n; k++)
    for(int i = 1; i <= n; i++)
        for(int j = 1; j <= n; j++)
            d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= n; j++) if(i != j)
        {
            if(ans < d[i][j])
            {
                ans = d[i][j];
            }
        }
    }
    if(fabs(ans - INF) < 1e-4) printf("Send Kurdy\n");
    else printf("%.4lf\n", ans);
}

int main()
{
    int T;
    scanf("%d", &T);
    int times = 0;
    while(T--)
    {
        init();
        scanf("%d", &n);
        for(int i = 1; i <= n; i++) scanf("%lf%lf", &a[i].x, &a[i].y);
        for(int i = 1; i <= n; i++)
        {
            for(int j = 1; j <= n; j++) if(i != j)
            {
                double w = dist(a[i], a[j]);
                if(w > 10) w = INF;
                d[i][j] = d[j][i] = w;
            }
        }
        printf("Case #%d:\n", ++times);
        Floyd();
        printf("\n");
    }
    return 0;
}