Lesson overview · Free interview practice

Tree BFS

Traverse trees level by level using Breadth-First Search.

Topics in the full lesson
  • Concept and Use Cases
  • When to Use
  • Time and Space Complexity
  • Level-Order Traversal of a Binary Tree
  • Finding the Minimum Depth of a Binary Tree
  • Finding the Largest Value in Each Tree Row

Practice Problems

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CodingEasy

Average of Levels in Binary Tree

Question

Given the root of a binary tree, return an array in which the i-th element is the average of the values of the nodes on the i-th level (the root is level 0).

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Practice on LeetCode
CodingMedium

Binary Tree Zigzag Level Order Traversal

Question

Given a binary tree, traverse its nodes in a zigzag level order traversal pattern, alternating the order of traversal between left-to-right and right-to-left within each level of the tree.

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Practice on LeetCode
CodingMedium

Binary Tree Level Order Traversal II

Question

Given the root of a binary tree, return its bottom-up level order traversal: the levels ordered from the leaf level up to the root, with node values within each level listed from left to right.

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Practice on LeetCode

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