Submission #1000737

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Source Code Expand

#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <numeric>
#include <random>
#include <vector>
#include <array>
#include <bitset>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>

using namespace std;
using ll = long long;
using ull = unsigned long long;
constexpr ll TEN(int n) { return (n==0) ? 1 : 10*TEN(n-1); }
int bsr(int x) { return 31 - __builtin_clz(x); }

int main() {
    ios::sync_with_stdio(0);
    cout << setprecision(20);
    int n;
    cin >> n;
    int sm = 0;
    vector<int> v;
    for (int i = 0; i < n; i++) {
        int a;
        cin >> a;
        sm ^= a;
        v.push_back(a^(a-1));
    }
    sort(v.begin(), v.end(), greater<int>());
    int co = 0;
    for (int d: v) {
        if (bsr(d) == bsr(sm)) {
            co++;
            sm ^= d;
        }
    }
    if (sm) {
        cout << -1 << endl;
    } else {
        cout << co << endl;
    }
    return 0;
}

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