BST

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# CSCI-UA 102
## Data Structures

## BST - Implementation

.author[
Instructor: Joanna Klukowska 
]

.license[
Copyright 2020 Joanna Klukowska. Unless noted otherwise all content is released under a 
[Creative Commons Attribution-ShareAlike 4.0 International License](https://creativecommons.org/licenses/by-sa/4.0/). 
Background image by Stewart Weiss ]

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.bottom-left[© Joanna Klukowska. CC-BY-SA.]

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### What does this tree look like?

```java
tree.add("salmon");
tree.add("flounder");
tree.add("grouper");
tree.add("cod");
tree.add("carp");
tree.add("tilapia");
tree.add("catfish");
tree.add("bluefish");
tree.add("tuna");
tree.add("yellowtail");
tree.add("herring");
tree.add("sturgeon");
```

With your group, draw out the tree that results from the
above sequence of `add` operations. Assume you start with an
empty tree.

Use [Google Jamboard](https://jamboard.google.com/)
to draw it in a collaborative way.
Use the name "breakout room NUM" in which you replace NUM with the number of your breakout room.
Share it with jk157@nyu.edu as well as all your room members.

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### What is this?

.left-column2[
.smaller[
```
salmon
|--flounder
   |--cod
      |--carp
         |--bluefish
            |--->
            |--->
         |--catfish
            |--->
            |--->
      |--->
   |--grouper
      |--->
      |--herring
         |--->
         |--->
|--tilapia
   |--sturgeon
      |--->
      |--->
   |--tuna
      |--->
      |--yellowtail
         |--->
         |--->

```
]]
.right-column2[
Try to answer the following questions:
- what does the _drawing_ on the left represent?
- how does it relate to the tree that you drew in the previous step?
- can you come up with an algorithm that produces that kind of output
given a binary search tree?

When we come back to the main room, some rooms will get a chance to answer these
questions, so make sure you can explain your answers.

]

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.red[WARNING: you will not be able to start this part until after we discuss the previous parts
in the main room. ]

### Implement the `add`

- One person in your room should open the Ed workspace that contains the skeleton for the BST class.
That person should share the workspace with the other members of the room and with jk157@nyu.edu.
__Do not make it public.__

- Rename your workspace `BST-breakout-NUM` in which you replace `NUM` with the number of your workspace.

- Implement the `add` method using a recursive approach.
This should be collaborative work and discussion, not parallel development.
Decide what needs to be checked and how things should be validated. Make sure that you think
of any special cases (for example, adding to an empty tree or adding a duplicate of an existing value).

When we come back to the main room, some rooms will get a chance to showcase their code
so make sure you keep it _presentable_.

</optgroup>