Complement of Base 10 Integer

1class Solution {
2    public int bitwiseComplement(int n) {
3        if (n == 0) {
4            return 1;
5        }
6
7        int i = 30;
8        while (i >= 0) {
9            int bit = n & (1 << i);
10            if (bit > 0) {
11                break;
12            }
13            i--;
14        }
15
16        int mask = (1 << i + 1) - 1;
17        return ~n & mask; 
18    }
19}