UVA 10491 Cows and Cars——概率水题

#include <cstdio>#include <cstring>using namespace std;int main() {    int a, b, c;    while (scanf("%d %d %d", &a, &b, &c) == 3) {        double ans1 = 1.0 * b / (1.0 * a + b) * 1.0 * (b - 1) / (1.0 * a - c + b - 1);        double ans2 = 1.0 * a / (1.0 * a + b) * 1.0 * b / (1.0 * a - c + b - 1);        printf("%.5lf\n", ans1 + ans2);    }    return 0;}