1009. Complement of Base 10 Integer (feat.PYTHON)

1009. Complement of Base 10 Integer

Easy

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:

1. 0 <= N < 10^9

풀이:

입력받은 10진수 숫자를 2진수로 바꾼 뒤 2로 나눈 나머지값을 더해 결과를 구합니다.

class Solution(object):
    def bitwiseComplement(self, N):
        N , B, result, mul, i = int(N), 0, 0, 1, 1

        while N > 0:
            binary = N % 2
            B += binary * i
            i = i * 10
            N = N // 2

        while B > 0:
            if B % 2 == 0:
                result += mul
            mul *= 2
            B = B // 10

        return result

N을 6이라 했을 때, 2진수는 1110이다. 따라서 보수는 0001이 됩니다.

N을 2로 나눈 나머지 값이 0이면 1을 1이면 0을 해당 자리 수 값에 곱해서 정답에 더합니다.