* Add "reference" for EN version. Bug fixes.
* Unify the figure reference as "the figure below" and "the figure above".
Bug fixes.
* Format the EN markdown files.
* Replace "" with <u></u> for EN version and bug fixes
* Fix biary_tree_dfs.png
* Fix biary_tree_dfs.png
* Fix zh-hant/biary_tree_dfs.png
* Fix heap_sort_step1.png
* Sync zh and zh-hant versions.
* Bug fixes
* Fix EN figures
* Bug fixes
* Fix the figure labels for EN version
* fix: Correcting typos
* Add JavaScript and TypeScript code of dynamic programming.
* fix: Code Style
* Change ==/!= to ===/!==
* Create const by default, change to let if necessary.
* style fix: Delete unnecessary defined type
Yudong Jin
gaofer