Loading your interview setup

Skip to content

Overview Resume Score

Practice

The Daily LarpCode Reps LarpTalk

Interview

Templates Sessions

recent

Loading

medium· trees Mock interview

Binary Tree Zigzag Level Order Traversal

Given the root of a binary tree, return its zigzag level-order traversal: left to right on the first level, right to left on the next, alternating each level.

Examples

in: root = [3,9,20,null,null,15,7]

out: [[3],[20,9],[15,7]]

directions alternate by level

Constraints

0 <= number of nodes <= 2000
-100 <= node value <= 100

Hints

target: O(n) time⌘↩ run · ⇧⌘↩ submit