# Source Map — 07 Trees

Reference করা প্রতিটা idea আর problem কোথা থেকে এসেছে, আর এখানে কীভাবে ব্যবহার হয়েছে। এই folder-এর সব prose, ASCII tree আর code এই repo-র জন্য scratch থেকে লেখা।

| Concept / Problem | Source Type | Source Name | Link | How it is used | Copying status |
| --- | --- | --- | --- | --- | --- |
| Tree / binary tree terminology | Encyclopedia | Wikipedia: Binary tree | <https://en.wikipedia.org/wiki/Binary_tree> | concept.md-র vocabulary cross-check | original explanation |
| BST definition and operations | Encyclopedia | Wikipedia: Binary search tree | <https://en.wikipedia.org/wiki/Binary_search_tree> | Invariant-এর ভাষা আর O(h) cost-এর verification | original explanation |
| Tree traversal orders | Encyclopedia | Wikipedia: Tree traversal | <https://en.wikipedia.org/wiki/Tree_traversal> | in/pre/post/level definition-গুলোর cross-check | original explanation |
| BST chapter (rigorous treatment) | Open textbook | Open Data Structures | <https://opendatastructures.org/> | গভীরে follow-up পড়ার suggestion | official link only |
| Trees in Python, traversal exercises | Open textbook | Problem Solving with Algorithms and DS (Runestone) | <https://runestone.academy/ns/books/published/pythonds3/index.html> | Supplementary beginner reading | official link only |
| Binary tree chapter with diagrams | Open book | Hello Algo | <https://www.hello-algo.com/en/> | Recommend করার মতো বিকল্প visual treatment | official link only |
| Interactive BST animations | Interactive tool | VisuAlgo | <https://visualgo.net/en> | Recommended interactive practice | official link only |
| Tree algorithms for CP (Euler tour, tree DP) | CP reference | CP-Algorithms | <https://cp-algorithms.com/> | Competitive গভীরতার জন্য forward pointer | official link only |
| CP tree curriculum | CP curriculum | USACO Guide | <https://usaco.guide/> | README-র CP connection | official link only |
| Binary Tree Inorder Traversal | Online judge | LeetCode | <https://leetcode.com/problems/binary-tree-inorder-traversal/> | Traversal practice-এর anchor | official link only |
| Maximum Depth of Binary Tree | Online judge | LeetCode | <https://leetcode.com/problems/maximum-depth-of-binary-tree/> | Height pattern-এর anchor, নিজের ভাষায় | rewritten problem |
| Validate Binary Search Tree | Online judge | LeetCode | <https://leetcode.com/problems/validate-binary-search-tree/> | Bounds-validation-এর centerpiece, নিজের ভাষায় | rewritten problem |
| Binary Tree Level Order Traversal | Online judge | LeetCode | <https://leetcode.com/problems/binary-tree-level-order-traversal/> | Queue-BFS worked pattern, নিজের ভাষায় | rewritten problem |
| LCA of a Binary Search Tree | Online judge | LeetCode | <https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/> | LCA-in-BST worked sketch, নিজের ভাষায় | rewritten problem |
| Diameter of Binary Tree | Online judge | LeetCode | <https://leetcode.com/problems/diameter-of-binary-tree/> | Diameter-via-height worked pattern, নিজের ভাষায় | rewritten problem |
| Path Sum | Online judge | LeetCode | <https://leetcode.com/problems/path-sum/> | Path-pattern-এর worked sketch, নিজের ভাষায় | rewritten problem |
| Same Tree, Invert, Symmetric, others | Online judge | LeetCode | <https://leetcode.com/problems/> + slug per README | Practice list-এর entry | official link only |
| Subordinates | Online judge | CSES 1674 | [মূল প্রশ্ন](https://cses.fi/problemset/task/1674) | অধ্যায়ের অনুশীলন ও ধারণার reference | official link only |
| Tree Diameter | Online judge | CSES 1131 | [মূল প্রশ্ন](https://cses.fi/problemset/task/1131) | অধ্যায়ের অনুশীলন ও ধারণার reference | official link only |
| Recursion foundation | This repo | 06 Recursion and Backtracking | ../06-recursion-and-backtracking/ | Prerequisite + leap-of-faith-এর reuse | original explanation |
| Stack/queue engines for traversals | This repo | 04 Stack and Queue | ../04-stack-and-queue/ | Iterative DFS-এর stack আর BFS-এর queue link | original explanation |
| Family-tree / folders analogy, all diagrams | This repo | concept.md, visual-explanation.md | ./concept.md | Original framing device | original explanation |
| All implementation.py code | This repo | implementation.py | ./implementation.py | Scratch থেকে লেখা; assert দিয়ে verify করা | original explanation |