Hierarchy Level Collect (Hard)

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Hierarchy Level Collect

Hard

Trees

In "Hierarchy Level Collect", 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 = [11,12,13,null,14,15,null]

Output:[[11],[12,13],[14,15]]

For input root = [11,12,13,null,14,15,null], nodes are grouped by depth from top to bottom, yielding [[11],[12,13],[14,15]]. Therefore, return [[11],[12,13],[14,15]].

Example 2

Input:root = [21,22,23,24,null,null,25]

Output:[[21],[22,23],[24,25]]

For input root = [21,22,23,24,null,null,25], nodes are grouped by depth from top to bottom, yielding [[21],[22,23],[24,25]]. Therefore, return [[21],[22,23],[24,25]].

Constraints

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

solution.js

Test Cases (2)

Test Case 1

Input:

[11,12,13,null,14,15,null]

Expected Output:

[[11],[12,13],[14,15]]

Test Case 2

Input:

[21,22,23,24,null,null,25]

Expected Output:

[[21],[22,23],[24,25]]