2040.cpp

杭电 acm部分代码 有兴趣的可以下载 谢谢

#include <iostream>
using namespace std;
double len[22];
int k;
bool flag, use[22];

void dfs(double now, int choose)
{
	if (flag == true || choose >= k)
	{
		return;
	}
	if (now == 0 && choose != 0)
	{
		flag = true;
	}
	dfs (now + len[choose], choose + 1);
	dfs (now, choose + 1);
	dfs (now - len[choose], choose + 1);
}

int main()
{
	int i;
	while (scanf("%d", &k) == 1)
	{
		memset (use, false, sizeof(use));
		for (i = 0; i < k; i++)
		{
			scanf("%lf", &len[i]);
		}
		flag = false;
		dfs(0, 0);
		dfs(len[1], 0);
		if (flag == true)
		{
			printf("YES\n");
		}
		else 
		{
			printf("NO\n");
		}
	}
	return 0;
}