bzoj1800

简直暴力。。

#include <cstdio>

int sum[30],n;

int read_int () {
	char c = getchar();
	int re = 0;
	for(;c > '9' || c < '0';c = getchar());
	for(;c >= '0' && c <= '9';c = getchar())
		re = re * 10 + c - '0';
	return re;
}

int main () {
	
	n = read_int();
	
	for(int i = 1;i <= n;++i) {
		sum[i] += read_int();
		sum[i + 1] = sum[i];
	}
	
	int ans = 0;
	for(int i = 1;i <= n - 3;++i) {
		for(int j = i + 1;j <= n - 2;++j) {
			for(int k = j + 1;k <= n - 1;++k) {
				for(int l = k + 1;l <= n;++l) {
					int t1 = sum[j - 1] - sum[i - 1];
					int t2 = sum[l - 1] - sum[k - 1];
					int t3 = sum[k - 1] - sum[j - 1];
					int t4 = sum[n] - sum[l - 1] + sum[i - 1];
					if(t1 == t2 && t3 == t4)
						++ans;
				}
			}
		}
	}
	printf("%d\n",ans);
}