1770F - Koxia and Sequence - CodeForces Solution

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

void solve(int tcId) {
    int n, x, y;
    cin >> n >> x >> y;

    if (n % 2 == 0) {
        cout << "0\n";
        return;
    }

    int ans = 0;

    for (int msk = y; msk; msk = (msk - 1) & y) {
        for (int bit = 0; bit < 20; bit++) {
            if (msk & ((int)1 << bit)) {
                if (((x - ((int)1 << bit)) & (n * msk - ((int)1 << bit))) == (x - ((int)1 << bit)))
                    ans ^= (int)1 << bit;
            }
        }
    }

    cout << ans << '\n';
}

signed main() {
    bool multi = false;
    if (!multi) {
        solve(42);
    } else {
        int t;
        cin >> t;
        while (t--)
            solve(t);
    }
}