Binary Tree Level Order Traversal

MediumTreesBFS

Solve this the way you would in the interview: out loud, on a timer, with an AI interviewer asking follow-ups while you code. You get a scored report at the end.

Practice this as a mock interviewFree to start, no account needed

Problem

Given the root of a binary tree, return the level order traversal of its nodes' values (i.e., from left to right, level by level).

Examples

Input: root = [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]
Input: root = [1]
Output: [[1]]
Input: root = []
Output: []

Constraints

  • The number of nodes in the tree is in the range [0, 2000].
  • -1000 <= Node.val <= 1000

What the interviewer grades

A correct solution is one of five scores. The report also grades problem understanding (did you clarify inputs and edge cases before coding), problem solving, communication while you work, code quality, and testing. See a sample report, or read up on the pattern in the lessons.

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