1009. Complement of Base 10 Integer

/*
Every non-negative integer N has a binary representation.  For example, 5 can be represented as "101" in binary, 11 as "1011" in binary, and so on.  Note that except for N = 0, there are no leading zeroes in any binary representation.

The complement of a binary representation is the number in binary you get when changing every 1 to a 0 and 0 to a 1.  For example, the complement of "101" in binary is "010" in binary.

For a given number N in base-10, return the complement of it's binary representation as a base-10 integer.

 

Example 1:

Input: 5
Output: 2
Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.
Example 2:

Input: 7
Output: 0
Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.
Example 3:

Input: 10
Output: 5
Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.
 

Note:

0 <= N < 10^9




*/
public class Solution {
    public int BitwiseComplement(int N) {
       List<int> list = new List<int>();
        
        string s = Convert.ToString(N,2);
        
      string s1 = "";
        
        foreach(char ch in s)
            s1 +=   ch == '0' ? "1" : "0";
        
        return Convert.ToInt32(s1,2);
        
        
        
    }
}