Make Array Elements Equal to Zero

Description

You are given an integer array nums.

Start by selecting a starting position curr such that nums[curr] == 0, and choose a movement direction of either left or right.

After that, you repeat the following process:

- If curr is out of the range [0, n - 1], this process ends.

- If nums[curr] == 0, move in the current direction by incrementing curr if you are moving right, or decrementing curr if you are moving left.

- Else if nums[curr] > 0:


- Decrement nums[curr] by 1.

- Reverse your movement direction (left becomes right and vice versa).

- Take a step in your new direction.





A selection of the initial position curr and movement direction is considered valid if every element in nums becomes 0 by the end of the process.

Return the number of possible valid selections.