HackerEarth Natural XOR elements problem solution

In this HackerEarth Natural XOR elements problem solution You are given an integer N. To solve the problem, you must find the minimum number of elements that must be removed from the set S = {1,2,..., N} such that the bitwise XOR of the remaining elements is 0.

HackerEarth Natural XOR elements problem solution.

#include <iostream>
using namespace std;

#define mod 1000000007
#define fi first
#define se second

int main(int argc, char *argv[]) {
    int t;
    cin >> t;
    while (t--) {
        int n, xo;
        cin >> n;
        switch (n % 4) {
            case 0:
                cout << "1 " << n << "\n";
                break;
            
            case 1:
                cout << "1 " << 1 << "\n";
                break;

            case 2:
                cout << "2 " << n << " " << (n ^ n + 1) << "\n";
                break;

            default:
                cout << "0\n";
                break;
        }
    }
    return 0;
}