* no need to clone in hash put fn
* fmt rust code
* make code more readable
* Change vec append to extend, more friendly to rookie rust dev
* drop comment
* Update copyright
* Update the Python code
* Fix the code comments in ArrayBinaryTree
* Fix the code comments in ArrayBinaryTree
* Roll back time_comlexity.py
* Add the visualizing code(pythontutor) blocks to the chapter complexity, data structure, array and linked list, stack and queue, hash table, and backtracking
* Fix the code comments
* Sync recent changes to the revised Word.
* Revised the preface chapter
* Revised the introduction chapter
* Revised the computation complexity chapter
* Revised the chapter data structure
* Revised the chapter array and linked list
* Revised the chapter stack and queue
* Revised the chapter hashing
* Revised the chapter tree
* Revised the chapter heap
* Revised the chapter graph
* Revised the chapter searching
* Reivised the sorting chapter
* Revised the divide and conquer chapter
* Revised the chapter backtacking
* Revised the DP chapter
* Revised the greedy chapter
* Revised the appendix chapter
* Revised the preface chapter doubly
* Revised the figures
* feat: add rust codes for avl tree
* fix a wrong usage of borrow method of RefCell
* Update avl_tree.rs
* fix comment indentation and field define of TreeNode
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Co-authored-by: Yudong Jin <krahets@163.com>
