Counting Bits

Counting Bits

Bitwise Operator Version - 108ms

class Solution:
    def countBits(self, num):
        """
        :type num: int
        :rtype: List[int]
        """
        res = [0]
        for i in range(1, num + 1):
            res.append(res[i >> 1] + (i & 1))
        return res

test code

In [147]: s = Solution(); t = s.countBits(5); print(t)
[0, 1, 1, 2, 1, 2]

leet code