高消0pts 玄关求助

#include <bits/stdc++.h>
typedef long long ll;

using namespace std;

const int N = 110;
int n, t, a[N], b[N];
ll tot, ans;

int main() {
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &a[i]), b[i] = a[i];
		tot += 0ll + a[i];
	}
	t = n;
	for (int i = 1; i <= n; i++) {
		for (int j = i + 1; j <= n; j++) if (a[j] > a[i])
			swap(a[i], a[j]), swap(b[i], b[j]);
		if (!a[i]) {
			t = i - 1;
			break;
		}
		for (int j = 30; j >= 0; j--) if (a[i] >> j & 1)
			for (int k = 1; k <= n; k++) if (i != k && a[k] >> j & 1)
				a[k] ^= a[i];
	}
	for (int i = 1; i <= t; i++)
		ans += 0ll + b[i];
	printf("%lld\n", ans == 0 ? -1 : tot - ans);
	return 0;
}