Submission #2011133

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Source Code Expand

#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<climits>
#include<iostream>
#include<string>
#include<stack>
#include<queue>
#include<vector>
#include<map>
#include<set>
#include<algorithm>
#include<numeric>
#include<bitset>

#define rep(n) for(int i=0;i<n;i++)
#define repp(j, n) for(int j=0;j<n;j++)
#define reppp(i, m, n) for(int i=m;i<n;i++)
#define all(c) c.begin(), c.end()
#define rall(c) c.rbegin(), c.rend()
#define MOD 1000000007
#define EPS 1e-9
 
using namespace std;

typedef long long ll;
typedef pair<ll, ll> Pll;
typedef pair<int, int> Pii;
struct edge{int from, to; ll cost;};

int main(){
    std::ios::sync_with_stdio(0); cin.tie(0);
    int n;
    cin >> n;
    unsigned long a;
    bitset<32> aa = 0;
    vector<unsigned long> b;
    rep(n){
        cin >> a;
        aa ^= bitset<32>(a);
        b.push_back(a^(a-1));
    }
    sort(rall(b));
    unique(all(b));
    int i = 31, ans = 0;
    for(auto b_n : b){
        bitset<32> b = bitset<32>(b_n);
        while(i >= 0 && !aa.test(i)) i--;
        if(i == -1) break;
        if(aa.test(i) && b.test(i)){
            aa ^= b;
            ans++;
        }
    }
    if(aa.any()) ans = -1;
    cout << ans << endl;
    return 0;
}

Submission Info

Judge Result