add binary-search-tree

config.json

@@ -569,6 +569,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "binary-search-tree",
+        "name": "Binary Search Tree",
+        "uuid": "4caa6234-719f-4548-b4ee-521407248751",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "camicia",
         "name": "Camicia",

exercises/practice/binary-search-tree/.docs/instructions.md

@@ -0,0 +1,70 @@
+# Instructions
+
+Insert and search for numbers in a binary tree.
+
+When we need to represent sorted data, an array does not make a good data structure.
+
+Say we have the array `[1, 3, 4, 5]`, and we add 2 to it so it becomes `[1, 3, 4, 5, 2]`.
+Now we must sort the entire array again!
+We can improve on this by realizing that we only need to make space for the new item `[1, nil, 3, 4, 5]`, and then adding the item in the space we added.
+But this still requires us to shift many elements down by one.
+
+Binary Search Trees, however, can operate on sorted data much more efficiently.
+
+A binary search tree consists of a series of connected nodes.
+Each node contains a piece of data (e.g. the number 3), a variable named `left`, and a variable named `right`.
+The `left` and `right` variables point at `nil`, or other nodes.
+Since these other nodes in turn have other nodes beneath them, we say that the left and right variables are pointing at subtrees.
+All data in the left subtree is less than or equal to the current node's data, and all data in the right subtree is greater than the current node's data.
+
+For example, if we had a node containing the data 4, and we added the data 2, our tree would look like this:
+
+![A graph with root node 4 and a single child node 2.](https://assets.exercism.org/images/exercises/binary-search-tree/tree-4-2.svg)
+
+```text
+      4
+     /
+    2
+```
+
+If we then added 6, it would look like this:
+
+![A graph with root node 4 and two child nodes 2 and 6.](https://assets.exercism.org/images/exercises/binary-search-tree/tree-4-2-6.svg)
+
+```text
+      4
+     / \
+    2   6
+```
+
+If we then added 3, it would look like this
+
+![A graph with root node 4, two child nodes 2 and 6, and a grandchild node 3.](https://assets.exercism.org/images/exercises/binary-search-tree/tree-4-2-6-3.svg)
+
+```text
+       4
+     /   \
+    2     6
+     \
+      3
+```
+
+And if we then added 1, 5, and 7, it would look like this
+
+![A graph with root node 4, two child nodes 2 and 6, and four grandchild nodes 1, 3, 5 and 7.](https://assets.exercism.org/images/exercises/binary-search-tree/tree-4-2-6-1-3-5-7.svg)
+
+```text
+          4
+        /   \
+       /     \
+      2       6
+     / \     / \
+    1   3   5   7
+```
+
+## Credit
+
+The images were created by [habere-et-dispertire][habere-et-dispertire] using [PGF/TikZ][pgf-tikz] by Till Tantau.
+
+[habere-et-dispertire]: https://exercism.org/profiles/habere-et-dispertire
+[pgf-tikz]: https://en.wikipedia.org/wiki/PGF/TikZ

exercises/practice/binary-search-tree/.gitignore

@@ -0,0 +1,3 @@
+.pyret/
+*.jarr
+node_modules

exercises/practice/binary-search-tree/.meta/config.json

@@ -0,0 +1,18 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "binary-search-tree.arr"
+    ],
+    "test": [
+      "binary-search-tree-test.arr"
+    ],
+    "example": [
+      ".meta/example.arr"
+    ]
+  },
+  "blurb": "Insert and search for numbers in a binary tree.",
+  "source": "Josh Cheek"
+}

exercises/practice/binary-search-tree/.meta/example.arr

@@ -0,0 +1,30 @@
+use context starter2024
+
+provide-types *
+
+provide: binary-search-tree end
+
+data BinarySearchTree:
+  | empty-tree with:
+    method insert(_, new-value):
+      tree-node(new-value, empty-tree, empty-tree)
+    end,
+    method sorted-data(_):
+      [list: ]
+    end
+  | tree-node(value, left, right) with:
+    method insert(self, new-value):
+      if new-value <= self.value:
+        tree-node(self.value, self.left.insert(new-value), self.right)
+      else:
+        tree-node(self.value, self.left, self.right.insert(new-value))
+      end
+    end,
+    method sorted-data(self):
+      self.left.sorted-data() + [list: self.value] + self.right.sorted-data()
+    end
+end
+
+fun binary-search-tree(values):
+  values.foldl(lam(value, tree): tree.insert(value) end, empty-tree)
+end

exercises/practice/binary-search-tree/.meta/tests.toml

@@ -0,0 +1,40 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[e9c93a78-c536-4750-a336-94583d23fafa]
+description = "data is retained"
+
+[7a95c9e8-69f6-476a-b0c4-4170cb3f7c91]
+description = "insert data at proper node -> smaller number at left node"
+
+[22b89499-9805-4703-a159-1a6e434c1585]
+description = "insert data at proper node -> same number at left node"
+
+[2e85fdde-77b1-41ed-b6ac-26ce6b663e34]
+description = "insert data at proper node -> greater number at right node"
+
+[dd898658-40ab-41d0-965e-7f145bf66e0b]
+description = "can create complex tree"
+
+[9e0c06ef-aeca-4202-b8e4-97f1ed057d56]
+description = "can sort data -> can sort single number"
+
+[425e6d07-fceb-4681-a4f4-e46920e380bb]
+description = "can sort data -> can sort if second number is smaller than first"
+
+[bd7532cc-6988-4259-bac8-1d50140079ab]
+description = "can sort data -> can sort if second number is same as first"
+
+[b6d1b3a5-9d79-44fd-9013-c83ca92ddd36]
+description = "can sort data -> can sort if second number is greater than first"
+
+[d00ec9bd-1288-4171-b968-d44d0808c1c8]
+description = "can sort data -> can sort complex tree"

exercises/practice/binary-search-tree/binary-search-tree-test.arr

@@ -0,0 +1,73 @@
+use context starter2024
+
+include file("binary-search-tree.arr")
+
+check "data is retained":
+  binary-search-tree([list: 4]) is tree-node(4, empty-tree, empty-tree)
+end
+
+check "insert data at proper node -> smaller number at left node":
+  expected = tree-node(4,
+    tree-node(2, empty-tree, empty-tree),
+    empty-tree)
+
+  binary-search-tree([list: 4, 2]) is expected
+end
+
+check "insert data at proper node -> same number at left node":
+  expected = tree-node(4,
+    tree-node(4, empty-tree, empty-tree),
+    empty-tree)
+
+  binary-search-tree([list: 4, 4]) is expected
+end
+
+check "insert data at proper node -> greater number at right node":
+  expected = tree-node(4,
+    empty-tree,
+    tree-node(5, empty-tree, empty-tree))
+
+  binary-search-tree([list: 4, 5]) is expected
+end
+
+check "can create complex tree":
+  expected = tree-node(4,
+    tree-node(2,
+      tree-node(1, empty-tree, empty-tree),
+      tree-node(3, empty-tree, empty-tree)),
+    tree-node(6,
+      tree-node(5, empty-tree, empty-tree),
+      tree-node(7, empty-tree, empty-tree)))
+
+  binary-search-tree([list: 4, 2, 6, 1, 3, 5, 7]) is expected
+end
+
+check "can sort data -> can sort single number":
+  tree = binary-search-tree([list: 2])
+
+  tree.sorted-data() is [list: 2]
+end
+
+check "can sort data -> can sort if second number is smaller than first":
+  tree = binary-search-tree([list: 2, 1])
+
+  tree.sorted-data() is [list: 1, 2]
+end
+
+check "can sort data -> can sort if second number is same as first":
+  tree = binary-search-tree([list: 2, 2])
+
+  tree.sorted-data() is [list: 2, 2]
+end
+
+check "can sort data -> can sort if second number is greater than first":
+  tree = binary-search-tree([list: 2, 3])
+
+  tree.sorted-data() is [list: 2, 3]
+end
+
+check "can sort data -> can sort complex tree":
+  tree = binary-search-tree([list: 2, 1, 3, 6, 7, 5])
+
+  tree.sorted-data() is [list: 1, 2, 3, 5, 6, 7]
+end

exercises/practice/binary-search-tree/binary-search-tree.arr

@@ -0,0 +1,26 @@
+use context starter2024
+
+provide-types *
+
+provide: binary-search-tree end
+
+data BinarySearchTree:
+  | empty-tree with:
+    method insert(_, new-value):
+      raise("please implement the insert method")
+    end,
+    method sorted-data(_):
+      raise("please implement the sorted-data method")
+    end
+  | tree-node(value, left, right) with:
+    method insert(_, new-value):
+      raise("please implement the insert method")
+    end,
+    method sorted-data(_):
+      raise("please implement the sorted-data method")
+    end
+end
+
+fun binary-search-tree(values):
+  raise("please implement the binary-search-tree function")
+end

exercises/practice/binary-search-tree/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "@exercism/pyret",
+  "description": "Exercism exercises in Pyret.",
+  "author": "Katrina Owen",
+  "contributors": [
+    "BNAndras"
+  ],
+  "private": true,
+  "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/pyret"
+  },
+  "scripts": {
+    "test": "pyret *-test.arr"
+  },
+  "dependencies": {
+    "pyret-npm": "0.0.90"
+  },
+  "packageManager": "npm@11.13.0"
+}