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: 4Output: 2

Example 2:

Input: 8Output: 2

Explanation:

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

class Solution {    public int mySqrt(int x) {            if (0 == x){            return 0;        }        int left = 1;        int right = x, ans=0;        while (left <= right){            int mid = left + (right - left)/2;            if (mid <= x/mid){                left = mid + 1;                ans = mid;            }else{                right = mid -1;            }        }        return ans;    }}