Day_4.Number Complement

Problem Statement
Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation.

 

Example 1:

Input: 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: 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.
 

Note:

The given integer is guaranteed to fit within the range of a 32-bit signed integer.
You could assume no leading zero bit in the integer’s binary representation.
Soln
def findComplement(self, num: int) -> int:
        def decimalToBinary(N):
            res = 0
            while N>=1:
                temp = math.floor(math.log2(N))
                res+=10**temp     
                N = N-2**temp
            return res
        def binaryToDecimal(N):
            res = 0
            count = 0
            lst = list(str(N))
            while lst:
                temp = int(lst.pop())
                if temp==1:
                    res+=2**count
                count+=1
            return res
        def complement(num):
            lst=[str(int(i) ^ 1) for i in str(num)]
            p="".join(lst)
            return p.lstrip('0')
        p=decimalToBinary(num)
        q=complement(p)
        result=binaryToDecimal(q)
        return result