Submission #1247854

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Source Code Expand

#include <bits/stdc++.h>
#include <iomanip>

using namespace std;

typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef long double LD;
typedef pair<LD, LD> PLDLD;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define CLR(a) memset((a), 0 ,sizeof(a))
#define ALL(a) a.begin(),a.end()

const double eps=1e-5;
const LL INF=1e15;

int main()
{
    int n;
    cin>>n;
    vector<PII> a(n+1);
    REP(i,n)
    {
        int s;
        cin>>s;
        a[i]=PII(s,0);
    }

    int sum=0;
    int ans=0;
    bool flag=1;
    for(int k=30;k>=0;k--)
    {
    sort(ALL(a),greater<PII>());
        sum=0;
        for(int i=0;i<a.size();i++)
        {
            sum^=(1<<k)&a[i].first;
            if(a[i+1].first<(1<<k))
            {
                if(sum!=0)
                {
                    if(a[i]==PII(1<<k, 0))
                    {
                        a[i]=PII(a[i].first-1,1);
                        ans++;
                    }
                    else
                    {
                        flag=0;
                    }
                }
                break;
            }
            a[i].first-=(1<<k);
        }
    }

    if(!flag)ans=-1;
    cout<<ans<<endl;
}

Submission Info

Judge Result