Given the `root` of a binary tree and an integer `limit`, delete all insufficient nodes in the tree simultaneously, and return the root of the resulting binary tree.

A node is insufficient if every root to leaf path intersecting this node has a sum strictly less than `limit`.

A leaf is a node with no children.

Example 1:

    Input: root = [1,2,3,4,-99,-99,7,8,9,-99,-99,12,13,-99,14], limit = 1
    Output: [1,2,3,4,null,null,7,8,9,null,14]

Example 2:

    Input: root = [5,4,8,11,null,17,4,7,1,null,null,5,3], limit = 22
    Output: [5,4,8,11,null,17,4,7,null,null,null,5]

Example 3:

    Input: root = [1,2,-3,-5,null,4,null], limit = -1
    Output: [1,null,-3,4]

Constraints:

- The number of nodes in the tree is in the range `[1, 5000]`.
- `-105 <= Node.val <= 105`
- `-109 <= limit <= 109`