Review of Weeks 7, 8, and 9: Binary trees; counting
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Weeks 7, 8, and 9 spanned over the Spring Break and were interrupted by the COVID-19 outbreak. As we transitioned from face-to-face to online class meetings, we discussed the concept of data structures and, specifically, binary trees, binary search trees, tree traversal algorithms, and decision trees.

 **Reading material about trees:**

* From the recommended textbook: Chapters 9.5, 9.6, and 9.7.

* `L. Lovasz and K. Vesztergombi's have an advanced chapter on trees <https://github.com/lgreco/cdp/blob/master/source/COMP163/OER/LovaszVesztergombi-trees.pdf>`_. (Published on L. Lovasz's website).


 **Reading material about counting:**


* From the recommended textbook: Chapters 6.1, 6.2, 6.3, and 6.4.

* `O. Levin's section counting <https://github.com/lgreco/cdp/blob/master/source/COMP163/OER/Levin-counting.pdf>`_. (Made available under a CC BY SA license).
* `Aspnes' chapter on counting <https://github.com/lgreco/cdp/blob/master/source/COMP163/OER/Aspnes-counting.pdf>`_. (Made available under a CC BY SA license).