71 lines
2.2 KiB
Markdown
71 lines
2.2 KiB
Markdown
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# Binary Search Tree
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Insert and search for numbers in a binary tree.
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When we need to represent sorted data, an array does not make a good
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data structure.
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Say we have the array `[1, 3, 4, 5]`, and we add 2 to it so it becomes
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`[1, 3, 4, 5, 2]` now we must sort the entire array again! We can
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improve on this by realizing that we only need to make space for the new
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item `[1, nil, 3, 4, 5]`, and then adding the item in the space we
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added. But this still requires us to shift many elements down by one.
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Binary Search Trees, however, can operate on sorted data much more
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efficiently.
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A binary search tree consists of a series of connected nodes. Each node
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contains a piece of data (e.g. the number 3), a variable named `left`,
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and a variable named `right`. The `left` and `right` variables point at
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`nil`, or other nodes. Since these other nodes in turn have other nodes
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beneath them, we say that the left and right variables are pointing at
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subtrees. All data in the left subtree is less than or equal to the
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current node's data, and all data in the right subtree is greater than
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the current node's data.
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For example, if we had a node containing the data 4, and we added the
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data 2, our tree would look like this:
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4
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/
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2
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If we then added 6, it would look like this:
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4
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/ \
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2 6
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If we then added 3, it would look like this
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4
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/ \
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2 6
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\
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3
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And if we then added 1, 5, and 7, it would look like this
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4
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/ \
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/ \
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2 6
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/ \ / \
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1 3 5 7
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## Submitting Exercises
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Note that, when trying to submit an exercise, make sure the solution is in the `exercism/python/<exerciseName>` directory.
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For example, if you're submitting `bob.py` for the Bob exercise, the submit command would be something like `exercism submit <path_to_exercism_dir>/python/bob/bob.py`.
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For more detailed information about running tests, code style and linting,
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please see the [help page](http://exercism.io/languages/python).
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## Source
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Wikipedia [https://en.wikipedia.org/wiki/Binary_search_tree](https://en.wikipedia.org/wiki/Binary_search_tree)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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