Submission #1244548

---

Source Code Expand

#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <algorithm>
#include <sstream>
#include <cmath>
#include <set>
#include <iomanip>
#include <deque>
#include <stdio.h>
#include <fstream>
using namespace std;

#define REP(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define RREP(i,n) for(int (i)=(int)(n)-1;i>=0;i--)
#define REMOVE(Itr,n) (Itr).erase(remove((Itr).begin(),(Itr).end(),n),(Itr).end())
#define UNIQUE(Itr) sort((Itr).begin(),(Itr).end()); (Itr).erase(unique((Itr).begin(),(Itr).end()),(Itr).end())
#define LBOUND(Itr,val) lower_bound((Itr).begin(),(Itr).end(),(val))
#define UBOUND(Itr,val) upper_bound((Itr).begin(),(Itr).end(),(val))
typedef long long ll;
#define MOD 1000000007

int judge(int n) {
    ll t = 2;
    REP(i,29) {
        if((t<<i)-1 == n) return i;
    }
    return -1;
}

int main() {
    
    int N; cin >> N;
    vector<int> a(N);
    REP(i,N) cin >> a[i];
    
    int x = 0;
    REP(i,N) x ^= a[i];
    
    if(x == 0) {
        cout << 0 << endl;
        return 0;
    }
    
    bool exist[32];
    REP(i,32) exist[i] = false;
    
    REP(i,N) {
        int t = a[i] ^ (a[i] - 1);
        if(judge(t) != -1) exist[judge(t)] = true;
    }
    
    int cnt = 0;
    for(int i=30;i>=0;i--) {
        if((x>>i)&1) {
            if(exist[i]) {
                x ^= ((2<<i)-1);
                cnt++;
            }
        }
    }
    
    if(x == 0) cout << cnt << endl;
    else cout << -1 << endl;
    
    return 0;
}

Submission Info

Judge Result