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BASA DSA

Binary Tree Level Order Traversal

MediumTrees

Return binary tree values grouped by depth, from the root down and from left to right within each level.

Example 1

Argument 1 tree: level-order input; omitted children are null.Argument 1 tree: level-order input; omitted children are null. Vertices: node 0: 1, node 1: 2, node 2: 3, node 3: 4. Edges: node 0 (1) — node 1 (2) left child; node 0 (1) — node 2 (3) right child; node 1 (2) — node 3 (4) right child.1234
Argument 1 tree: level-order input; omitted children are null.

Input
root = [1,2,3,null,4]
Output
[[1],[2,3],[4]]

Explanation

Read root [1], children [2,3], then the only grandchild [4].

Example 2

Argument 1 tree: empty tree (null root).
Input
root = []
Output
[]

Explanation

An empty tree has no levels.

Example 3

Argument 1 tree: level-order input; omitted children are null.Argument 1 tree: level-order input; omitted children are null. Vertices: node 0: 8. Edges: none.8
Argument 1 tree: level-order input; omitted children are null.

Input
root = [8]
Output
[[8]]

Explanation

A leaf gives one level containing 8.

Constraints

  • 0 <= number of nodes <= 2000
  • Trees are breadth-first arrays with null holes

Function contractlevelOrderArguments: tree
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