[leetcode] Sqrt(x)

Implement int sqrt(int x).

Compute and return the square root of x.

class Solution {
public:
    int sqrt(int x) {
		// Start typing your C/C++ solution below
		// DO NOT write int main() function
		if(x<=0)
			return 0;
		if(x==1)
			return 1;
		int left=1,right=x/2;
		int middle=0;
		while(left<=right){
			middle=((right-left)>>1)+left;
			int temp=middle*middle;
			if(temp>x || temp/middle!=middle)
				right=middle-1;
			else if(middle*middle<x && temp/middle==middle)
				left=middle+1;
			else
				return middle;
		}
		return right;
	}
};