Sqrt(x)

public class Solution {
    public int sqrt(int x) {
        if(x <=0 ) return 0;
        int left = 1;
        int right = (int)Math.ceil(((long)x+1)/2);
        int rst = -1;
        long diff = Long.MAX_VALUE;
        while(left <= right)
        {
            int mid = (left + right)/2;
            long tmp = (long)mid*mid;
            if(tmp == x)
            {
                return mid;
            }
            if(tmp > x) right = mid - 1;
            else
            {
               left = mid + 1; 
               if(Math.abs(tmp - x) < diff){
                    rst = mid;
                    diff = Math.abs(tmp - x);
                }
            }
        }
        return rst;
    }
}

public class Solution {
    public int sqrt(int x) {
        if (x == 1 || x == 0) {
            return x;
        }
        
        int left = 1;
        int right = x;
        
        while (left < right - 1) {
            int mid = left + (right - left) / 2;
            int quo = x / mid;
            
            if (quo == mid) {
                return quo;
            // mid is too big    
            } else if (quo < mid) {
                right = mid;
            } else {
                left = mid;
            }
        }
        
        return left;
    }
}