#include <bits/stdc++.h>
using namespace std;
#define ll long long
ll c [50];
inline ll cal (int n) {
	ll sum1= 0,sum2=0;
	for(int i=1;i<=n/2;i++)sum1+=c[i];
	for(int i=n/2+1;i<=n;i++)sum2+=c[i];
	return abs(sum1-sum2);
}
ll ans = 0;
inline void solve () {
	int n;cin >> n;
	for (int i = 1;i <= n;++ i) cin >> c [i];
	if (n == 1) {
		cout << c [1] << endl;
		return ;
	}
	int times = 1000;
	ans = cal (n);
	while (times --) {
		for (double t = 10000;t >= 1e-10;t *= 0.95) {
			int a = (int)(rand ()) % n + 1;
			int b = (int)(rand ()) % n + 1;
			swap (c [a],c [b]);
			ll rt = cal (n);
			if (rt < ans) {
				ans = rt;
			} else if (exp ((ans - rt) / t) * RAND_MAX < rand ()) {
				swap (c [a],c [b]);
			}
		}
	}
	cout << ans << endl;
}
int main () {
#ifndef ONLINE_JUDGE
	freopen ("shit.txt","r",stdin);
#endif
	ios::sync_with_stdio (false);
	srand (time (NULL));
	int t;cin >> t;
	while (t --) solve ();
	return 0;
}

这段代码里:

int a = (int)(rand ()) % n + 1;
int b = (int)(rand ()) % n + 1;

为什么rand()如果乘了t就WA...调了两个小时参数..............