Link is as bear（线性基）

代码

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>

using namespace std;

typedef long long ll;

const int N = 65;

int n;
ll b[N];

void ins(ll x)
{
    for(int i = 62; i >= 0; i --) {
        if(x >> i & 1) {
            if(!b[i]) {
                b[i] = x;
                return;
            }
            else x ^= b[i];
        }
    }
}

ll find_max()
{
    ll ans = 0;
    for(int i = 62; i >= 0; i --) {
        ans = max(ans, ans ^ b[i]);
    }
    return ans;
}

int main()
{
    int T;
    scanf("%d", &T);
    while(T --) {
        scanf("%d", &n);
        memset(b, 0, sizeof b);
        for(int i = 1; i <= n; i ++) {
            ll x;
            scanf("%lld", &x);
            ins(x);
        }
        ll ans = find_max();
        printf("%lld\n", ans);
    }
    return 0;
}