uva 11181 - Probability|Given(概率）

#include <stdio.h>  
#include <string.h>  
const int N = 30;  
  
int n;  
double p[N], ans[N];  
  
double dfs(int c, int k, double pi) {  
    if (c > n) return k ? 0 : pi;  
  
    double sum = 0;  
    if (k) {  
        sum += dfs(c + 1, k - 1, pi * p[c]);  
        ans[c] += sum;  
    }  
  
    sum += dfs(c + 1, k, pi * (1 - p[c]));  
    return sum;  
}  
  
int main () {  
    int r, cas = 1;  
    while (scanf("%d%d", &n, &r), n + r) {  
        for (int i = 1; i <= n; i++)  
            scanf("%lf", &p[i]);  
        memset(ans, 0, sizeof(ans));  
  
        printf("Case %d:\n", cas++);  
        double P = dfs(1, r, 1);  
  
        for (int i = 1; i <= n; i++)  
            printf("%.6lf\n", ans[i] / P);  
    }  
    return 0;  
}