[Leetcode By Python]69. Sqrt(x)

题目：

Implement 

int sqrt(int x)

.
Compute and return the square root of x.
x is guaranteed to be a non-negative integer.

Example 1:

Input: 4
Output: 2

Example 2:

Input: 8
Output: 2
Explanation: The square root of 8 is 2.82842..., and since we want to return an integer, the decimal part will be truncated.

代码＋调试：

class Solution(object):
def mySqrt(self, x):
"""
:type x: int
:rtype: int
"""
if x==0:
return 0
i = 1;j=x/2+1
while i<=j:
mid = (i+j)/2
if mid**2 == x:
return mid
elif mid**2>x:
j = mid-1
else:
i = mid+1
return j

a = Solution()
print a.mySqrt(8)