Submission #1001607

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Source Code Expand

#include <vector>
#include <iostream>
using namespace std;
int n;
int main() {
	cin >> n;
	vector<int> a(n);
	for (int i = 0; i < n; i++) cin >> a[i];
	vector<int> p(n);
	int ret = 0;
	bool flag = true;
	for (int i = 29; i >= 0 && flag; i--) {
		int s = 0;
		for (int j = 0; j < n; j++) s ^= (a[j] >> i) & 1;
		if (s == 0) continue;
		bool ok = false;
		for (int j = 0; j < n && !ok; j++) {
			if (p[j] == 1) continue;
			if (a[j] >> i << i == a[j]) {
				p[j] = 1; a[j]--; ret++;
				ok = true;
			}
		}
		if (!ok) flag = false;
	}
	cout << (flag ? ret : -1) << endl;
	return 0;
}

Submission Info

Judge Result