sqrt(x)

[xqian]

http://leetcode.com/onlinejudge#question_69

Reference:
https://en.wikipedia.org/wiki/Newton's_method
http://fisherlei.blogspot.com/2013/01/leetcode-sqrtx.html

If the machine support float number, I will use float number and newton's method, finding the nearest int for the problem.

[waveletus]

Good idea to try classic problem in github.