LeetCode

Q：
Description:

Count the number of prime numbers less than a non-negative number, n.

A：

class Solution(object):    def countPrimes(self, n):        """        :type n: int        :rtype: int        """        if n == 0 or n == 1:            return 0        nums = [1] * n        nums[0] = nums[1] = 0        for i in range(2, int(n ** 0.5)+1):            if nums[i] != 0:                j = i * i                while j < n:                    nums[j] = 0                    j += i        return sum(nums)

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