class Solution {
    public int bitwiseComplement(int n) {
        if (n == 0) {
            return 1;
        }

        int i = 30;
        while (i >= 0) {
            int bit = n & (1 << i);
            if (bit > 0) {
                break;
            }
            i--;
        }

        int mask = (1 << i + 1) - 1;
        return ~n & mask; 
    }
}