Submission #4972400

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

int n;
vector<int> v;
int s;

int solve(){
	for(int i=0; i<n; ++i)
		s ^= v[i];
	if(s == 0) return -1;
	int t = 0;
	while((s >> t) > 0) ++t;
	--t;
//	cout << t << "\n";
	int f = 1;
	vector<int> w(1, t);
	for(int i=t-1; i>=0; --i){
		if(((s>>i)&1) != f){
			w.push_back(i);
			f = 1 - f;
		}
	}
	vector<int> x(w.size(), 0);
	int res = 0;
	for(int i=0; i<n; ++i){
		int u = 0;
		while(((v[i]>>u)&1) == 0) ++u;
		for(int j=0; j<w.size(); ++j){
			if(w[j] == u && x[j] == 0){
				++res;
				x[j] = 1;
			}
		}
	}
	for(int i=0; i<x.size(); ++i)
		if(x[i] == 0)
			return -1;
	return res;
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cin >> n;
	v.resize(n);
	for(auto &i:v) cin >> i;
//	sort(v.begin(), v.end());
	cout << solve() << "\n";
}

Submission Info

Judge Result