666. Path Sum IV

If the depth of a tree is smaller than 5, then this tree can be represented by an array of three-digit integers. You are given an ascending array nums consisting of three-digit integers representing a binary tree with a depth smaller than 5, where for each integer:

• The hundreds digit represents the depth d of this node, where 1 <= d <= 4.
• The tens digit represents the position p of this node within its level, where 1 <= p <= 8, corresponding to its position in a full binary tree.
• The units digit represents the value v of this node, where 0 <= v <= 9.

Return the sum of all paths from the root towards the leaves.

It is guaranteed that the given array represents a valid connected binary tree.

Example 1:

Example 2:

Constraints:

• 1 <= nums.length <= 15
• 110 <= nums[i] <= 489
• nums represents a valid binary tree with depth less than 5.
• nums is sorted in ascending order.