索引是从0开始的，索引6左边的所有数的和为0

10 -80 + 10 + 10 + 15 + 35 = 0 and right of the 20 (index 6) there is no other number, that counts as 0 too. It's similar to the last example in the description.

Can you help me, my question is how can I ask the second length of a two dimensional array.

      for(int i = 0; i < before.length; i++){
        int[][] rotors = new int[before.length][before[i].length()];
      }

This is how I see the creation of rotors. But the array will only work inside the loop, how can I fix this?