Implement int sqrt(int x).

Compute and return the square root of x.

原题链接：https://oj.leetcode.com/problems/sqrtx/

使用二分法来解题。

	public int sqrt(int x) {
		if(x == 0 || x== 1)
			return x;
		int left = 1,right = x,temp=0;
		while(left <= right){
			int mid = (left+right)/2;
			if(mid == x/mid)
				return mid;
			else if(mid > x/mid)
				right = mid - 1;
			else{
				left = mid+1;
				temp = mid;
			}
		}
		return temp;
	}

LeetCode——Sqrt(x)