位运算

//https://oj.neauacm.cn/problem.php?cid=1206&pid=10
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2e5+9;
int a[N],sum[N];
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        memset(sum,0,sizeof(sum));
        int n;
        long long ans = 0;
        scanf("%d",&n);
        for(int i=1; i<=n; i++) scanf("%d",&a[i]),ans |= a[i];
        if(n != 1)
        {
            int high = 30;
            for(int i=high; i>=0; i--)
            {
                for(int j=1; j<=n; j++)
                {
                    sum[i] += ((a[j] >> i) & 1); //统计每一位1的个数！
                }
            }
            long long minn = 1e18+101001;
            long long bak = ans;
            for(int i=1; i<=n; i++)
            {
                ans = bak;
                for(int j=high; j>=0; j--)
                {
                    if(sum[j] == 1 && ((a[i]>>j) & 1))
                    {
                        ans = ans ^ (1<<j); //把j位置为0；
                    }
                }
                minn = min(min(minn,(ans|(a[i]>>1))),ans|a[i]); 
            }
            printf("%lld\n",minn);
        }
        else printf("%d\n",a[1]);
    }
    return 0;
}