Submission #3261345

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Source Code Expand

#include <bits/stdc++.h>
#define FOR(i, a, b) for(int i=(int)(a); i!=(int)(b); i++)
#define RFOR(i, a, b) for(int i=(int)(a); i!=(int)(b); i--)
#define REP(i, n) FOR(i, 0, n)
#define bit(n) (1LL << (n))
using namespace std;
using ll = long long;

int bits(int n){
  int cnt = 0;
  while(n){
    n >>= 1;
    cnt++;
  }
  return cnt-1;
}

int main(){
  int n; cin >> n;
  vector<int> a(n), ch(32);
  int x=0; 
  REP(i, n){
    cin >> a[i];
    x ^= a[i];
    ch[bits(a[i]^a[i-1])]++;
  }

  bitset<32> b(x);
  int ans = 0;
  RFOR(i, 31, -1){
    if(b[i]){
      if(ch[i] == 0){
        cout << -1 << endl;
        return 0;
      }
      x ^= (bit(i+1)-1);
      ans++;
      b = bitset<32>(x);
    }
  }

  if(x == 0){
    cout << ans << endl;
  }
  else{
    cout << -1 << endl;
  }

  return 0;
}

Submission Info

Judge Result