Leetcode-633 (两数平方和)

import math
class Solution:
    def judgeSquareSum(self, c: int) -> bool:
        if c < 0:
            return False

        #如果c不是0
        start = 0
        end = int(math.sqrt(c))+1
        while start <= end:
            if start*start + end *end ==c:
                return True
            elif start*start + end *end >c:
                end-=1
            else:
                start+=1
        else:
            return False