HDU 4815 Little Tiger vs. Deep Monkey

#include <cstdio>
using namespace std;

#define N 40001

int a[40];
double dp[N];

int main() {
    int t, n;
    double p;
    scanf("%d", &t);
    while (t--) {
        scanf("%d%lf", &n, &p);
        dp[0] = 1;
        for (int i = 1; i < N; i++) {
            dp[i] = 0;
        }
        int tot = 0;
        for (int i = 0; i < n; i++) {
            scanf("%d", &a[i]);
            tot += a[i];
        }
        for (int i = 0; i < n; i++) {
            for (int j = tot; j >= 0; j--) {
                if (a[i] > j) {
                    dp[j] *= 0.5;
                }
                else {
                    dp[j] = (dp[j] + dp[j - a[i]]) * 0.5;
                }
            }
        }
        for (int i = 0; i <= tot; i++) {
            p -= dp[i];
            if (p <= 1e-6) {
                printf("%d\n", i);
                break;
            }
        }
    }
    return 0;
}