Code : Minimum XOR Pair

#include <bits/stdc++.h>
using namespace std;

void solve(vector<int> &a) {
    int n = a.size();
    sort(a.begin(), a.end());
    int res = (1 << 30) - 1;
    for (int i = 1; i < n; i++) {
        res = min(res, a[i] ^ a[i - 1]);
    }
    cout << res << endl;
}

int main() {
    int t;
    cin >> t;
    for (int zz = 0; zz < t; zz++) {
        int n;
        cin >> n;
        vector<int> a(n);
        for (int i = 0; i < n; i++) {
            cin >> a[i];
        }
        solve(a);
    }
    return 0;
}