Decision Tree Layer Walk (Hard)

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Decision Tree Layer Walk

Hard

Trees

In "Decision Tree Layer Walk", the binary tree is provided in array form (level-order with null gaps).

Return node values grouped by depth from top to bottom and left to right.

Example 1

Input:root = [8,9,10,null,11,12,null]

Output:[[8],[9,10],[11,12]]

For input root = [8,9,10,null,11,12,null], nodes are grouped by depth from top to bottom, yielding [[8],[9,10],[11,12]]. Therefore, return [[8],[9,10],[11,12]].

Example 2

Input:root = [18,19,20,21,null,null,22]

Output:[[18],[19,20],[21,22]]

For input root = [18,19,20,21,null,null,22], nodes are grouped by depth from top to bottom, yielding [[18],[19,20],[21,22]]. Therefore, return [[18],[19,20],[21,22]].

Constraints

0 <= number of nodes <= 2000
-1000 <= Node.val <= 1000

solution.js

Test Cases (2)

Test Case 1

Input:

[8,9,10,null,11,12,null]

Expected Output:

[[8],[9,10],[11,12]]

Test Case 2

Input:

[18,19,20,21,null,null,22]

Expected Output:

[[18],[19,20],[21,22]]