Leetcode练习<二十一>求解整数的平方根

”’
@greg 2017-08-24

Implement int sqrt(int x).

Compute and return the square root of x.

求解整数的平方根

class Solution():
    def mySqrt(self, x):
        '''
        当前值的平方小于x，下一个值的平方大于x，所以就返回x
        :param x:
        :return:
        '''
        if x == 1:
            return 1
        if x == 0:
            return 0
        half_x = x // 2
        for i in range(1, half_x+1):
            if i**2 <= x and (i+1) ** 2 > x:
                return i

    def mySqrt1(self, x):
        '''
        g的更新方式为g = (g + x / g) / 2
        迭代法求解
        :param x:
        :return:
        '''
        g = x
        while g*g-x > 0:
            g = (g + x / g) / 2
        return int(g)

if __name__ == '__main__':
    s = Solution()
    x = 3
    print(s.mySqrt1(x))