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.

public int mySqrt(int x) {
        if (x<=1) return x;
        int i=0,j=x;
        while (i<j){
            int mid=i+(j-i)/2;
            if (x/mid>=mid) {i=mid+1;}
            else {j=mid;}
        }
        return i;
    }