Third edition

package.json

@@ -71,12 +71,12 @@
     "istanbul": "^v1.1.0-alpha.1",
     "mocha": "^5.0.4",
     "mochawesome": "^3.0.2",
-    "nyc": "11.7.0",
+    "nyc": "11.7.1",
     "ts-node": "^5.0.1",
     "tslint": "^5.9.1",
     "typescript": "^2.7.2",
     "webpack": "^4.1.1",
-    "webpack-cli": "2.0.14",
+    "webpack-cli": "2.0.15",
     "yargs": "^11.0.0"
   },
   "dependencies": {

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

@@ -4,7 +4,7 @@ import { Node } from './models/node';
 export default class BinarySearchTree {
   constructor(compareFn = defaultCompare) {
     this.compareFn = compareFn;
-    this.root = null;
+    this.root = undefined;
   }
   insert(key) {
     // special case: first key
@@ -99,7 +99,7 @@ export default class BinarySearchTree {
   }
   removeNode(node, key) {
     if (node == null) {
-      return null;
+      return undefined;
     }
     if (this.compareFn(key, node.key) === Compare.LESS_THAN) {
       node.left = this.removeNode(node.left, key);
@@ -115,7 +115,7 @@ export default class BinarySearchTree {
     // 3 - a node with 2 children
     // case 1
     if (node.left == null && node.right == null) {
-      node = null;
+      node = undefined;
       return node;
     }
     // case 2

src/js/data-structures/models/node.js

@@ -1,8 +1,8 @@
 export class Node {
   constructor(key) {
     this.key = key;
-    this.left = null;
-    this.right = null;
+    this.left = undefined;
+    this.right = undefined;
   }
   toString() {
     return `${this.key}`;

test/js/algorithms/search/binary-search-recursive.spec.js

@@ -0,0 +1,5 @@
+import { binarySearchRecursive } from '../../../../src/js/index';
+import { testSearchAlgorithm } from './search-algorithms-tests';
+
+testSearchAlgorithm(binarySearchRecursive, 'Binary Search Recursive');
+

test/js/data-structures/avl-tree.spec.js

@@ -0,0 +1,32 @@
+import 'mocha';
+import { expect } from 'chai';
+import { AVLTree } from '../../../src/js/index';
+
+describe('AVLTree', () => {
+  let tree;
+
+  beforeEach(() => {
+    tree = new AVLTree();
+  });
+
+  it('starts empty', () => {
+    expect(tree.getRoot()).to.equal(null);
+  });
+
+  it('inserts elements in the AVLTree', () => {
+    expect(tree.getRoot()).to.equal(null);
+
+    tree.insert(1);
+    tree.insert(2);
+    tree.insert(3);
+    tree.insert(4);
+    tree.insert(5);
+    tree.insert(6);
+    tree.insert(7);
+    tree.insert(14);
+    tree.insert(15);
+    tree.insert(13);
+    tree.insert(12);
+    tree.insert(11);
+  });
+});

test/js/data-structures/binary-search-tree.spec.js

@@ -0,0 +1,108 @@
+import 'mocha';
+import { expect } from 'chai';
+import { BinarySearchTree } from '../../../src/js/index';
+
+describe('BinarySearchTree', () => {
+  let tree;
+
+  beforeEach(() => {
+    tree = new BinarySearchTree();
+  });
+
+  it('starts empty', () => {
+    expect(tree.getRoot()).to.equal(undefined);
+  });
+
+  function assertNode(node, key, left, right) {
+    if (key != null) {
+      expect(node.key).to.equal(key);
+    } else {
+      expect(node).to.equal(key);
+      return;
+    }
+
+    if (left != null) {
+      expect(node.left.key).to.equal(left);
+    } else {
+      expect(node.left).to.equal(left);
+    }
+
+    if (right != null) {
+      expect(node.right.key).to.equal(right);
+    } else {
+      expect(node.right).to.equal(right);
+    }
+  }
+
+  it('inserts elements in the BST', () => {
+    expect(tree.getRoot()).to.equal(undefined);
+
+    tree.insert(11);
+    tree.insert(7);
+    tree.insert(15);
+    tree.insert(5);
+    tree.insert(3);
+    tree.insert(9);
+    tree.insert(8);
+    tree.insert(10);
+    tree.insert(13);
+    tree.insert(12);
+    tree.insert(14);
+    tree.insert(20);
+    tree.insert(18);
+    tree.insert(25);
+
+    let node = tree.getRoot();
+    assertNode(node, 11, 7, 15);
+
+    node = node.left;
+    assertNode(node, 7, 5, 9);
+
+    node = node.left;
+    assertNode(node, 5, 3, undefined);
+
+    node = node.left;
+    assertNode(node, 3, undefined, undefined);
+
+    node = tree.getRoot().left.left.right;
+    assertNode(node, undefined, undefined, undefined);
+
+    node = tree.getRoot().left.right;
+    assertNode(node, 9, 8, 10);
+
+    node = node.left;
+    assertNode(node, 8, undefined, undefined);
+
+    node = tree.getRoot().left.right.right;
+    assertNode(node, 10, undefined, undefined);
+
+    node = tree.getRoot().right;
+    assertNode(node, 15, 13, 20);
+
+    node = node.left;
+    assertNode(node, 13, 12, 14);
+
+    node = node.left;
+    assertNode(node, 12, undefined, undefined);
+
+    node = tree.getRoot().right.left.right;
+    assertNode(node, 14, undefined, undefined);
+
+    node = tree.getRoot().right.right;
+    assertNode(node, 20, 18, 25);
+
+    node = node.left;
+    assertNode(node, 18, undefined, undefined);
+
+    node = tree.getRoot().right.right.right;
+    assertNode(node, 25, undefined, undefined);
+  });
+
+  it('verifies if element exists', () => {
+    expect(tree.getRoot()).to.equal(undefined);
+  });
+
+  it('removes a leaf', () => {
+    expect(tree.getRoot()).to.equal(undefined);
+  });
+});

test/js/data-structures/heap.spec.js

@@ -0,0 +1,75 @@
+import 'mocha';
+import { expect } from 'chai';
+import { MinHeap, heapSort } from '../../../src/js/index';
+
+describe('Heap', () => {
+  let heap;
+
+  beforeEach(() => {
+    heap = new MinHeap();
+  });
+
+  it('starts empty MinHeap', () => {
+    expect(heap.size()).to.equal(0);
+    expect(heap.isEmpty()).to.equal(true);
+  });
+
+  it('inserts values in the MinHeap', () => {
+    const resultArray = [];
+    for (let i = 1; i < 10; i++) {
+      resultArray.push(i);
+      heap.insert(i);
+      expect(heap.getAsArray()).to.deep.equal(resultArray);
+    }
+  });
+
+  it('finds the min value from the MinHeap', () => {
+    const resultArray = [];
+    for (let i = 10; i >= 1; i--) {
+      resultArray.push(i);
+      heap.insert(i);
+      expect(heap.findMinimum()).to.equal(i);
+    }
+  });
+
+  it('performs heapify in the MinHeap', () => {
+    const resultArray = [];
+    for (let i = 10; i >= 1; i--) {
+      resultArray.push(i);
+    }
+    expect(heap.heapify(resultArray)).to.deep.equal(resultArray);
+  });
+
+  it('extracts the min value from the MinHeap', () => {
+    let resultArray = [];
+    for (let i = 1; i < 10; i++) {
+      resultArray.push(i);
+      heap.insert(i);
+      expect(heap.getAsArray()).to.deep.equal(resultArray);
+    }
+
+    resultArray = [
+      [],
+      [2, 4, 3, 8, 5, 6, 7, 9],
+      [3, 4, 6, 8, 5, 9, 7],
+      [4, 5, 6, 8, 7, 9],
+      [5, 7, 6, 8, 9],
+      [6, 7, 9, 8],
+      [7, 8, 9],
+      [8, 9],
+      [9],
+      []
+    ];
+
+    for (let i = 1; i < 10; i++) {
+      expect(heap.extract()).to.equal(i);
+      expect(heap.getAsArray()).to.deep.equal(resultArray[i]);
+    }
+  });
+
+  it('Heap Sort', () => {
+    const array = [3, 2, 5, 6, 1, 7, 8, 9];
+
+    expect(heapSort(array)).to.deep.equal([1, 2, 3, 5, 6, 7, 8, 9]);
+  });
+});

test/ts/data-structures/heap.spec.ts

@@ -1,8 +1,6 @@
 import 'mocha';
 import { expect } from 'chai';
-import { MinHeap } from '../../../src/ts/index';
-import { MaxHeap } from '../../../src/ts/data-structures/heap';
-import heapSort from '../../../src/ts/algorithms/sorting/heap-sort';
+import { MinHeap, heapSort } from '../../../src/ts/index';
 
 describe('Heap', () => {
   let heap: MinHeap<number>;
@@ -55,7 +53,7 @@ describe('Heap', () => {
       [2, 4, 3, 8, 5, 6, 7, 9],
       [3, 4, 6, 8, 5, 9, 7],
       [4, 5, 6, 8, 7, 9],
-      [5, 7 , 6, 8, 9],
+      [5, 7, 6, 8, 9],
       [6, 7, 9, 8],
       [7, 8, 9],
       [8, 9],