Скачать или смотреть Binary Tree Zigzag Level Order Traversal Explained VISUALLY | Day 14

Welcome to Day 14 of my #30DaysofCode challenge with Educative!

Today we’re diving into a beautiful tree-traversal pattern that combines classic BFS with strategic directional flipping: Binary Tree Zigzag Level Order Traversal (LeetCode 103).

🌳 At first glance, this looks like a standard level-order traversal. What’s the twist? Every level alternates direction: left-to-right, then right-to-left, then left-to-right again. This simple variation forces you to think about:
✨Queue control
✨Output ordering
✨Layer-by-layer state tracking
✨How to build predictable structure on top of BFS


📘 In this video, I’ll break down the full thought process step-by-step:
• Understanding the traversal visually & why normal BFS isn’t enough
• How to track levels, children, and directions cleanly
• Three different ways to implement zigzag:
1) Reverse the list each level
2) Insert children at different ends
3) Use a deque for O(1) directional work

• When each approach makes sense depending on constraints
• Why the optimal solution runs in O(n) time
• How this pattern generalizes to other “layered but directional” problems

🔁 I’m learning and practicing daily through Educative’s #30DaysofCode challenge!
It’s been one of the best structures for sharpening problem-solving intuition, building consistency, and learning how to think algorithmically with confidence.

🚀 If you want to join me, start your own #30DaysofCode journey on Educative.io and use my link below for 10% off!
👉 Join the challenge: https://www.educative.io/unlimited?af...
👉 Follow my progress: #TheRuntimeDiaries

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🧠 Timestamps

00:00 Intro
00:22 Understanding the Problem
01:23 What is Zigzag?
01:58 Input + Output
02:28 Example
03:26 Edge Case: Single Node
03:59 Human Intuition
04:32 Optimized Approach Initial Intuition
05:08 Core Insight
05:42 BFS Refresher
06:28 Optimized Pseudocode Walkthrough
08:18 Optimized Code
08:50 Optimized Complexity Analysis
09:43 Common Pitfalls
10:42 Alternative Approach: Two Stacks
11:25 Key Takeaways
12:37 Outro

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🎨 By Ashley Bedford, Founder of The Runtime Diaries
Making complex code visual, simple, and actually fun.

#TheRuntimeDiaries #Educative #30DaysofCode #LeetCode #Python #BinaryTree #BFS #DataStructures #Algorithms #CodingChallenge