BZOJ 3105 新Nim游戏

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define maxn 105
using namespace std;
long long n,a[maxn],b[maxn],bit[32],ans=0,sum=0;
bool vis[32];
bool cmp(long long x,long long y)
{
    return x>y;
}
int main()
{
    scanf("%lld",&n);
    for (long long i=1;i<=n;i++) {scanf("%lld",&a[i]);sum+=a[i];}
    sort(a+1,a+n+1,cmp);
    for (long long i=1;i<=n;i++) b[i]=a[i];
    for (long long i=1;i<=n;i++)
        for (long long k=31;k>=0;k--)
        {
            if (!(a[i]&(1<<k))) continue;
            if (!vis[k]) 
                {vis[k]=true;ans+=b[i];bit[k]=a[i];break;}
            else a[i]^=bit[k];
        }
    printf("%lld\n",sum-ans);
    return 0;
}