Try thinking about the problem as if the array is empty. Then you only need to form goal using elements whose absolute value is <= limit.
提示 2
You can greedily set all of the elements except one to limit or -limit, so the number of elements you need is ceil(abs(goal)/ limit).
提示 3
You can "normalize" goal by offsetting it by the sum of the array. For example, if the goal is 5 and the sum is -3, then it's exactly the same as if the goal is 8 and the array is empty.
提示 4
The answer is ceil(abs(goal-sum)/limit) = (abs(goal-sum)+limit-1) / limit.
