Submission #2409577

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Source Code Expand

#include <iostream>
#include <string>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <map>
#include <cmath>
#include <queue>
#include <utility>
#include <functional>
#include <deque>
#include <cctype>
#include <stack>
#include <bitset>
#include <set>

using namespace std;
using ll = long long;
typedef unsigned long long ull;
typedef pair<ll, ll> P;

const ll MOD = 1e9 + 7;
const ll INF = 1 << 30;
const ll INF2 = 9e18;
const double INF3 = 9e14;
const int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };
const int tx[8] = { -1,0,1,-1,1,-1,0,1 }, ty[8] = { -1,-1,-1,0,0,1,1,1 };
#define ALL(x) (x).begin(),(x).end()
#define pb push_back
#define fr first
#define sc second



int main() {
	ll n, a, bit[50] = { 0 }, ans = 0, b1 = 0, b0 = 0;
		cin >> n;
		for (int i = 0;i<n;i++) {
			cin >> a;
			if (a&(1 << 0))b1++;
			else b0++;
			for (int j = 0;j <= 29;j++) {
				if (a&(1 << j))bit[j]++;
			}
		}


		for (int i = 29;i >= 1;i--) {
			if (bit[i] == 0)continue;
			if (bit[i] % 2 == 1) {
				if (b0 > 0) {
					ans++;
					b0--;
					for (int j = i;j >= 0;j--)bit[j] = (bit[j] + 1) % 2;
				}
				else {
					cout << -1 << endl;
					return 0;
				}
			}
		}
		if (bit[0] % 2 == 1) {
			if (b1 > 0)ans++, bit[0] = 0;
			else {
				cout << -1 << endl;
				return 0;
			}
		}
		for (int i = 0;i <= 29;i++) {
			if (bit[i] % 2 == 1) {
				cout << -1 << endl;
				return 0;
			}
		}
		cout << ans << endl;
	}

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