uva 10803 Thunder Mountain(最短路）

#include   
#include   
#include   
#include   
#define min(a,b) (a)<(b) (a):(b)  
#define max(a,b) (a)>(b) (a):(b)  
const int N = 105;  
const double INF = 1 << 30;  
  
int n;  
double ans, x[N], y[N], g[N][N];  
  
double distant(int a, int b) {  
    return sqrt( (x[a] - x[b]) * (x[a] - x[b] ) + (y[a] - y[b]) * (y[a] - y[b]) );  
}  
  
void input() {  
    scanf("%d", &n);  
    for (int i = 0; i < n; i++) {  
        scanf("%lf%lf", &x[i], &y[i]);  
        for (int j = 0; j < i; j++) {  
            double l = distant(i, j);  
            g[j][i] = g[i][j] = (l - 10.0 >





 1e-4   INF : l);  
        }  
    }  
}  
  
void Floyd() {  
    for (int k = 0; k < n; k++) {  
        for (int i = 0; i < n; i++) {  
            for (int j = 0; j < n; j++) {  
                g[i][j] = min(g[i][j], g[i][k] + g[k][j]);  
            }  
        }  
    }  
  
    ans = 0;  
    for (int i = 0; i < n; i++) {  
        for (int j = 0; j < n; j++) {  
            if (i != j)  
                ans = max(ans , g[i][j]);  
        }  
    }  
  
}  
  
int main () {  
    int cas, ti = 1;  
    scanf("%d", &cas);  
    while (cas--) {  
        input();  
        Floyd();  
        printf("Case #%d:\n", ti++);  
        if (fabs(ans - INF) < 1e-4) printf("Send Kurdy\n");  
        else printf("%.4lf\n", ans);  
        printf("\n");  
    }  
    return 0;  
}