Node Level Aggregation (Medium)

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Node Level Aggregation

Medium

Trees

In "Node Level Aggregation", 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 = [17,18,19,null,20,21,null]

Output:[[17],[18,19],[20,21]]

For input root = [17,18,19,null,20,21,null], nodes are grouped by depth from top to bottom, yielding [[17],[18,19],[20,21]]. Therefore, return [[17],[18,19],[20,21]].

Example 2

Input:root = [27,28,29,30,null,null,31]

Output:[[27],[28,29],[30,31]]

For input root = [27,28,29,30,null,null,31], nodes are grouped by depth from top to bottom, yielding [[27],[28,29],[30,31]]. Therefore, return [[27],[28,29],[30,31]].

Constraints

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

solution.js

Test Cases (2)

Test Case 1

Input:

[17,18,19,null,20,21,null]

Expected Output:

[[17],[18,19],[20,21]]

Test Case 2

Input:

[27,28,29,30,null,null,31]

Expected Output:

[[27],[28,29],[30,31]]