Sqrt(x)

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