leetcode1009

 class Solution:
     def bitwiseComplement(self, N: int) -> int:
         if N==0:
             return 1
         elif N==1:
             return 0

         s = list()
         while N!=0:
             re = N%2
             if re==0:
                 re=1
             else:
                 re = 0
             s.append(re)
             N=N//2
         sums = 0
         for i in range(len(s)):
             cur = int(s[i])
             cur = cur * pow(2,i)
             sums +=cur
         return sums