leetcode -- Sqrt(x)

Sqrt(x)

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.

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;
    }
}