476 Number Complement

1. Description

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 num, return its complement.

 

constraints :

• 1 <= num < \(2^{31}\)

2. Algorithms

To change each bit into complement in its binary representation, we have to chage "1" to "0" and "0" to "1".

 

1. Start
2. Declare variable binary_rep and initialize it with binary representation of input num.
3. Repeat the steps through the element of binary_rep.
   1. If current bit is "1", update current bit with "0".
   2. Else, update current bit with "1".
4. Return the result after changing binary representation to integer.
5. End

3. Codes

class Solution:
    def findComplement(self, num: int) -> int:
        # Store binary representation of input num. 
        binary_rep = list(bin(num))[2:]
        print(binary_rep)
        for i in range(len(binary_rep)) : 
            if binary_rep[i] == "1" : 
                binary_rep[i] = "0" 
            else :
                binary_rep[i] = "1" 
        
        return int("".join(binary_rep), 2)

4. Conclusion