687. Longest Univalue Path https://leetcode.com/problems/longest-univalue-path
865. Smallest Subtree with all the Deepest Nodes https://leetcode.com/problems/smallest-subtree-with-all-the-deepest-nodes
1026. Maximum Difference Between Node and Ancestor https://leetcode.com/problems/maximum-difference-between-node-and-ancestor
1339. Maximum Product of Splitted Binary Tree https://leetcode.com/problems/maximum-product-of-splitted-binary-tree
1372. Longest ZigZag Path in a Binary Tree https://leetcode.com/problems/longest-zigzag-path-in-a-binary-tree
606. Construct String from Binary Tree https://leetcode.com/problems/construct-string-from-binary-tree
1443. Minimum Time to Collect All Apples in a Tree https://leetcode.com/problems/minimum-time-to-collect-all-apples-in-a-tree
Prerequisite Knowledge
Before reading this article, you need to learn:
Basic binary tree functions like summing up values or finding the height are easy to write. Sometimes, you just need to add a bit of code in their post-order positions to get the desired results.
