2373.cpp

来自「哈尔滨工业大学ACM 竞赛网上在线试题集锦的源代码」· C++ 代码 · 共 37 行

/* This Code is Submitted by wywcgs for Problem 2373 on 2006-09-25 at 19:31:10 */
#include <cstdio>
#include <algorithm>
using namespace std;

int C(int, int);

int main()
{
	int n, m;
	
	while(scanf("%d %d", &n, &m) != EOF && n != 0) {
		for(int i = 1; i < n; i++) {
			int a; scanf("%d", &a);
			m -= a;
		}
		m -= n;
		int r = C(n-2, m+n-2);
		if(r < 0) printf("Too many ways.\n");
		else printf("%d\n", r);
	}
	
	return 0;
}

int C(int n, int m)
{
	if(n > m) return 0;
	if(n+n > m) n = m-n;
	int r = 1;
	for(int i = 1; i <= n; i++) {
		r = r*(m-i+1)/i;
		if(r > 10000) return -1;
	}
	return r;
}