Number Complement

Problem Statement - link #

The complement of an integer is the integer you get when you flip all the 0’s to 1’s and all the 1’s to 0’s in its binary representation.

• For example, The integer 5 is "101" in binary and its complement is "010" which is the integer 2.

Given an integer n, return its complement.

Examples #

Example 1:

Input: num = 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.

Example 2:

Input: num = 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.

Constraints #

• 0 <= n < 2^31

Solutions #

class Solution {
public:
    int findComplement(int n) {
      if(n==0) return 1;
      string b = "";
      while(n){
        b = (n%2==0? "1" : "0") + b;
        n/=2;
      }
      n = stoi(b,0,2);
      return n;
    }
};