Add binary search tree Jasmine tests

Signed-off-by: Darko Draskovic <[email protected]>

spec/binary-search-tree.spec.js

@@ -0,0 +1,25 @@
+import {
+ BinarySearchTree
+} from '../src/data-structures/binary-search-tree.js'
+
+describe("Function", function () {
+
+ const insert = [9, 4, 6, 5, 3, 20, 20, 170, 15, 1, 25, 300, 7, 30];
+ const remove = [9, 300, 25, 7, 25, 9, 9, 170, 15];
+
+ it(BinarySearchTree.name + " constructs binary search tree", function () {
+ const bst = new BinarySearchTree();
+
+ insert.forEach((value) => bst.insert(value));
+
+ insert.forEach((value) => expect(bst.lookup(value)).not.toBeNull());
+
+ remove.forEach((value) => bst.remove(value));
+
+ let difference = insert.filter(x => !remove.includes(x));
+
+ difference.forEach((value) => expect(bst.lookup(value)).not.toBeNull());
+
+ remove.forEach((value) => expect(bst.lookup(value)).toBeNull());
+ })
+})

src/algorithms/search.js

@@ -0,0 +1,23 @@
+// javascript built in search
+var beasts = ['Centaur', 'Godzilla',
+ 'Mosura', 'Minotaur', 'Hydra', 'Nessie'];
+
+(function test() {
+ // javascript built in linear searches; O(n)
+ console.assert(beasts.indexOf('Godzilla') == 1);
+ console.assert(beasts.indexOf('Cyclope') == -1);
+
+ console.assert(beasts.findIndex(function (item) {
+ return item == 'Hydra'
+ }) == 4);
+ console.assert(beasts.findIndex(function (item) {
+ return item == 'Cyclope'
+ }) == -1);
+
+ console.assert(beasts.find(function (item) {
+ return item == 'Hydra'
+ }) == 'Hydra');
+
+ console.assert(beasts.includes('Nessie') == true);
+ console.assert(beasts.includes('Cyclope') == false);
+})()

src/data-structures/binary-search-tree.js

@@ -6,7 +6,7 @@ export class Node {
  }
 }
 
-class BinarySearchTree {
+export class BinarySearchTree {
  constructor() {
  this.root = null;
  }
@@ -47,8 +47,10 @@ class BinarySearchTree {
  parent = current;
  current = current.right;
  } else {
- // current has two children => replace with successor
+ // we found value
+ // 1. current has two children => replace with successor
  if (current.left && current.right) {
+ // detach and rearrange left and right branch
  let successor = current.right;
  let successorParent = null;
  while (successor.left) {
@@ -61,13 +63,16 @@ class BinarySearchTree {
  successor.right = current.right;
  }
  if (!parent) {
+ // we removed root
  this.root = successor;
  } else {
+ // attach branch to parent's left
  if (current.value < parent.value) parent.left = successor;
+ // attach branch to parent's right
  else parent.right = successor;
  }
  return current;
- // current has one child => bypass current
+ // 2. current has one child => bypass current
  } else if (current.left || current.right) {
  // value is at the root
  if (!parent) {
@@ -83,7 +88,7 @@ class BinarySearchTree {
  else parent.right = current.right;
  }
  return current;
- // current has no children => remove current
+ // 3. current has no children => remove current
  } else {
  if (current.value < parent.value) parent.left = null;
  else parent.right = null;
@@ -115,7 +120,7 @@ function traverse(node) {
  return tree;
 }
 
-export function test() {
+(function test() {
  const bst = new BinarySearchTree();
  bst.insert(9);
  bst.insert(4);
@@ -141,8 +146,9 @@ export function test() {
  bst.remove(9); // remove non existing
  bst.remove(170);
  bst.remove(15); // root
- console.dir(traverse(bst.root), { depth: null });
 
- // console.log("================================")
- // console.log(bst.lookup(20));
-}
+ var tree = traverse(bst.root);
+ console.dir(tree, { depth: null });
+
+ console.log(bst.lookup(20));
+})()

src/index.js

@@ -1,3 +1,3 @@
-import { test } from './algorithms/recursion.js'
+import { test } from './algorithms/search.js'
 
-test();
+// test();