Count Nodes Equal to Average of Subtree | LEETCODE 2265 | Solve In Seconds

This video breaks down LeetCode 2265 — Count Nodes Equal to Average of Subtree — a medium binary tree problem where post-order DFS returns (sum, count) pairs to check the average condition at every node in linear time.

🚀 Cracking Amazon / Google interviews? Get every new LeetCode solution the moment it drops. Join 2,000+ coders who never miss a walkthrough:

📢 Telegram: https://t.me/opentech_shaanlabs
💬 WhatsApp: https://chat.whatsapp.com/CvlyO3ZBBoTBiPLDXpEJME?mode=gi_t
Count Nodes Equal to Average of Subtree is a medium binary tree problem asked in real interviews — DFS traversal computing subtree sum and count, checking the average condition at every node.

LeetCode Question: https://leetcode.com/problems/count-nodes-equal-to-average-of-subtree/ Solution (Java / Python / C++ / C): https://github.com/Shaanworkspace/YOUTUBE-DRIVE/blob/main/Leetcode_Daily/LC_2265_Count_Nodes_Equal_to_Average_of_Subtree_All_Languages.md

Why this approach beats the others
Post-order DFS returns (sum, count) — no competitor explains the two-value return pattern this clearly. We teach why children must be processed before parents.
O(n) vs O(n²) explained — brute force recalculates subtrees repeatedly. The optimal approach visits each node exactly once. We show both approaches side by side.
The average condition — node value equals floor(sum / count). We walk through exactly when this condition triggers and why integer division matters.
Pattern recognition — this same post-order aggregate pattern solves Maximum Average Subtree, Diameter of Binary Tree, and Binary Tree Maximum Path Sum.
Four-language code (Java/Python/C++/C) — no competitor provides all four with the same clean logic.
How to solve Count Nodes Equal to Average of Subtree (Step by Step)
Define a DFS helper that returns a pair: (subtree sum, subtree count).
Base case: null node returns (0, 0).
At each node, recursively get left and right pairs.
Compute sum = node.val + left.sum + right.sum, count = 1 + left.count + right.count.
If sum / count == node.val, increment the answer.
Return (sum, count) to the parent.
Notes for US interview prep
Title, description, tags, chapters = American English spelling.
Upload accurate English .srt captions (do NOT rely on auto-captions).
Schedule in EST window: Tue/Wed 2-4 PM EST (1:30 AM IST next day) via YouTube Schedule.
Long-form hashtags trimmed to 3 (LeetCode2265, CountNodesAverageSubtree, BinaryTreeDFS).
Create playlists: “LeetCode Daily”, “LeetCode Medium”, “Binary Tree DFS Patterns”.
Channel About section + keywords = US terms (LeetCode, coding interview, binary tree, DFS).
📺 Watch the full walkthrough on YouTube: https://youtu.be/cvpBMPbbRQc?si=9UmrodgirbT7IdqT

Watch the full Count Nodes Equal to Average of Subtree | LEETCODE 2265 | Solve In Seconds walkthrough on YouTube

🚀 Cracking Amazon / Google interviews? Get every new LeetCode solution the moment it drops. Join 2,000+ coders who never miss a walkthrough:

📢 Telegram: https://t.me/opentech_shaanlabs
💬 WhatsApp: https://chat.whatsapp.com/CvlyO3ZBBoTBiPLDXpEJME?mode=gi_t