Hackerrank Sum VS XOR

/**
 *    author:  compounding
 *    created: 2024-11-12 21:43:25
 **/
#include <bits/stdc++.h>
using namespace std;
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
#define NeedForSpeed                  \
    ios_base::sync_with_stdio(false); \
    cin.tie(NULL);                    \
    cout.tie(NULL);
#define int long long
#define all(x) (x).begin(), (x).end()
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vpi;
#define f first
#define s second
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define endl "\n"
const int mod = 1000000007;
int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }
void solve()
{
    // TODO: a^b = a+b; that means carry is 0 hence a&b = 0, as a+b = a^b + 2*(a&b)
    // hence a&b = 0, that means a and b have no common bits, if it's off in n then we have a choice of 2
    int n;
    cin >> n;
    int ans = 1;
    while (n)
    {
        if (!(n & 1))
        {
            ans <<= 1;
        }
        n >>= 1;
    }
    cout << ans << endl;
    return;
}

signed main()
{
    NeedForSpeed;
    int t = 1;
    // cin >> t;
    while (t--)
    {
        solve();
    }
    return 0;
}