Submission #2627047

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vl;

ll N;
ll ans = 0;

void solve() {
    cin >> N;
    multiset<ll> st;
    ll cur = 0;
    rep(i,N) {
        ll a;
        cin >> a;
        st.insert(a^(a-1));
        cur ^= a;
    }
    for (ll i = 30; i >= 0; --i) {
        if ((cur >> i) & 1) {
            if (!st.count((1 << (i+1)) - 1)) {
                cout << -1 << endl;
                return;
            }
            cur ^= (1 << (i+1)) - 1;
            ans++;
        }
    }
    cout << ans << endl;
}

int main() {
    cin.tie(0);
   	ios::sync_with_stdio(false);
    solve();
    return 0;
}

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