题目传送：UVA – 10375
思路：用double存答案，不过要注意是边乘边除，这样不会爆double，，还有记得乘的时候要把int转换成double
AC代码：
#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <cmath>#include <queue>#include <stack>#include <vector>#include <map>#include <set>#include <deque>#include <cctype>#define LL long long#define INF 0x7fffffffusing namespace std;int main() {int p, q, r, s;while(scanf("%d %d %d %d", &p, &q, &r, &s) != EOF) {double ans = 1;int len = max(p, r);for(int i = 1; i <= len; i ++) {if(i <= q) {ans *= (p * 1.0 – q + i) / i;}if(i <= s) {ans *= i * 1.0 / (r – s + i);}}printf("%.5lf\n", ans);}return 0;}
有希望在的地方，痛苦也成欢乐
