leetcode69题 二分法help see哪错了，为什么打印不出来

Question

public class demoEZ69 {
    public static void main(String[] args) {
        System.out.println(mySqrt(9));
    }

    public static int mySqrt(int x){ // when x == 25
         int l = 0, r = x, ans = -1;
         while(l <= r){ //while (l <= 25)  //4 <= 5
          int mid = 1 + (r-1) /2; // mid == 13  //mid == 6 //mid ==3
          if((long) mid* mid <= x){ //  if((long)169 <= 25)  //if((long)36 <= 25)
              ans = mid; //ans == 9 //ans == 3
              l = mid + 1;// l == 3 + 1 ==4

          }else{
              r = mid -1;  //r == 13 - 1 ==12 //r == 6-1 == 5
          }


         }
         return ans;
    }
}

Answer 1

小写的字母l和数字1

int mid = l+(r-l)/2,
代码的第8行