ComplementofBase10Integer.cpp

/*

Source: https://leetcode.com/problems/complement-of-base-10-integer/

Time: O(log base2 n), where n is the given number(num) and (log base2 n) means that the loop will iterate for a maximum of (log base2 n) times.
i.e. if n = 10, then the loop will iterate for 4((logn + 1) ~ logn) times. 6 times in case if n = 32.
Space: O(1), in-place

*/

class Solution {
public:
    int bitwiseComplement(int n) {

        if(n == 0) {
            return 1;
        }

        int complement = n;
        int mask = 1;

        while(n != 0) {

            complement ^= mask;
            mask <<= 1;
            n >>= 1;
        }

        return complement;
    }
};