Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.
实现sqrt(int x)函数。

class Solution:    # @param x, an integer    # @return an integer    def sqrt(self, x):        if x == 0 :            return x        if x == 1 or x == 2 or x == 3:            return 1        begin = 0        end = x        while begin < (end-1):            value = (begin + end) / 2            if value * value < x:                begin = value            elif value * value > x:                end = value            else:                begin = value                break        return begin