1611-minimum-one-bit-operations-to-make-integers-zero.cpp

class Solution {
public:
    int minimumOneBitOperations(int n, int res = 0) {
        if (n == 0) return res;
        int b = 1;
        while ((b << 1) <= n) b = b << 1;
        return minimumOneBitOperations((b >> 1) ^ b ^ n, res + b);
    }
};