chapter 08: [Recursion]

loiane · loiane · commit b6dfa0f28362 · 2017-11-18T13:30:21.000-02:00
diff --git a/.eslintrc.json b/.eslintrc.json
@@ -25,6 +25,7 @@
     "import/prefer-default-export": 0,
     "comma-dangle": 0,
     "no-underscore-dangle": 0,
-    "no-param-reassign": 0
+    "no-param-reassign": 0,
+    "no-return-assign": 0
   }
 }
diff --git a/README.md b/README.md
@@ -17,6 +17,7 @@ Work in Progress.
 * 05: [LinkedLists](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter05)
 * 06: [Sets](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter06)
 * 07: [Dictionaries and Hashes](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter07)
+* 08: [Recursion](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter08)
 
 ### Third Edition Updates
 
diff --git a/examples/PacktDataStructuresAlgorithms.min.js b/examples/PacktDataStructuresAlgorithms.min.js
diff --git a/examples/chapter08/01-IntroRecursion.html b/examples/chapter08/01-IntroRecursion.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title></title>
+</head>
+<body>
+  <script src="01-IntroRecursion.js"></script>
+</body>
+</html>
diff --git a/examples/chapter08/01-IntroRecursion.js b/examples/chapter08/01-IntroRecursion.js
@@ -0,0 +1,26 @@
+
+// functions commented below - inifite loop
+
+/*
+function recursiveFunction(someParam) {
+  recursiveFunction(someParam);
+}
+
+function recursiveFunction1(someParam) {
+  recursiveFunction2(someParam);
+}
+
+function recursiveFunction2(someParam) {
+  recursiveFunction1(someParam);
+}
+*/
+
+function understandRecursion(doIunderstandRecursion) {
+  const recursionAnswer = confirm('Do you understand recursion?'); // function logic
+  if (recursionAnswer === true) { // base case or stop point
+    return true;
+  }
+  understandRecursion(recursionAnswer); // recursive call
+}
+
+understandRecursion(false);
diff --git a/examples/chapter08/02-Factorial.html b/examples/chapter08/02-Factorial.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title></title>
+</head>
+<body>
+  <script src="02-Factorial.js"></script>
+</body>
+</html>
diff --git a/examples/chapter08/02-Factorial.js b/examples/chapter08/02-Factorial.js
@@ -0,0 +1,26 @@
+// @ts-check
+
+function factorialIterative(number) {
+  if (number < 0) {
+    return undefined;
+  }
+  let total = 1;
+  for (let n = number; n > 1; n--) {
+    total  = total * n;
+  }
+  return total;
+}
+
+console.log('factorialIterative(5): ', factorialIterative(5));
+console.log('factorialIterative(3): ', factorialIterative(3));
+
+function factorial(n) {
+  // console.trace();
+  if (n === 1 || n === 0) {
+    return 1;
+  }
+  return n * factorial(n - 1);
+}
+
+console.log('factorial(5): ', factorial(5));
+console.log('factorial(3): ', factorial(3));
diff --git a/examples/chapter08/03-JSCallStack.html b/examples/chapter08/03-JSCallStack.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title></title>
+</head>
+<body>
+  <script src="03-JSCallStack.js"></script>
+</body>
+</html>
diff --git a/examples/chapter08/03-JSCallStack.js b/examples/chapter08/03-JSCallStack.js
@@ -0,0 +1,11 @@
+let i = 0;
+function recursiveFn() {
+  i++;
+  recursiveFn();
+}
+
+try {
+  recursiveFn();
+} catch (ex) {
+  console.log('i = ' + i + ' error: ' + ex);
+}
diff --git a/examples/chapter08/04-Fibonacci.html b/examples/chapter08/04-Fibonacci.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title></title>
+</head>
+<body>
+  <script src="04-Fibonacci.js"></script>
+</body>
+</html>
diff --git a/examples/chapter08/04-Fibonacci.js b/examples/chapter08/04-Fibonacci.js
@@ -0,0 +1,43 @@
+function fibonacci(n){
+  if (n < 1) return 0; // {1}
+  if (n <= 2) return 1; // {2}
+  return fibonacci(n - 1) + fibonacci(n - 2); // {3}
+}
+
+console.log('fibonacci(2)', fibonacci(2));
+console.log('fibonacci(3)', fibonacci(3));
+console.log('fibonacci(4)', fibonacci(4));
+console.log('fibonacci(5)', fibonacci(5));
+
+function fibonacciIterative(n){
+  let fibNMinus2 = 0;
+  let fibNMinus1 = 1;
+  let fibN = n;
+  for (let i = 2; i <= n; i++) { // n >= 2
+    fibN = fibNMinus1 + fibNMinus2; // f(n-1) + f(n-2)
+    fibNMinus2 = fibNMinus1;
+    fibNMinus1 = fibN;
+  }
+  return fibN;
+}
+
+console.log('fibonacciIterative(2)', fibonacciIterative(2));
+console.log('fibonacciIterative(3)', fibonacciIterative(3));
+console.log('fibonacciIterative(4)', fibonacciIterative(4));
+console.log('fibonacciIterative(5)', fibonacciIterative(5));
+
+function fibonacciMemoization(n) {
+  const memo = [0, 1];
+  const fibonacci = (n) => {
+    if (memo[n] != null) return memo[n];
+    return memo[n] = fibonacci(n - 1, memo) + fibonacci(n - 2, memo);
+  };
+  return fibonacci(n);
+}
+
+console.log('fibonacciMemoization(2)', fibonacciMemoization(2));
+console.log('fibonacciMemoization(3)', fibonacciMemoization(3));
+console.log('fibonacciMemoization(4)', fibonacciMemoization(4));
+console.log('fibonacciMemoization(5)', fibonacciMemoization(5));
+
+// https://jsperf.com/fibonacci-comparison-jsbook
diff --git a/examples/index.html b/examples/index.html
@@ -45,6 +45,7 @@
         <a href="#scroll-tab-5" class="mdl-layout__tab">05</a>
         <a href="#scroll-tab-6" class="mdl-layout__tab">06</a>
         <a href="#scroll-tab-7" class="mdl-layout__tab">07</a>
+        <a href="#scroll-tab-8" class="mdl-layout__tab">08</a>
       </div>
     </header>
     <main class="mdl-layout__content">
@@ -173,6 +174,20 @@
         </div>
       </section>
       <section class="mdl-layout__tab-panel" id="scroll-tab-8">
+        <div class="page-content">
+          <div class="page-content mdl-layout--fixed-drawer">
+            <div class="mdl-layout__drawer is-visible">
+              <nav class="mdl-navigation">
+                <a class="mdl-navigation__link" href="chapter08/01-IntroRecursion.html">01-IntroRecursion</a>
+                <a class="mdl-navigation__link" href="chapter08/02-Factorial.html">02-Factorial</a>
+                <a class="mdl-navigation__link" href="chapter08/03-JSCallStack.html">03-JSCallStack</a>
+                <a class="mdl-navigation__link" href="chapter08/04-Fibonacci.html">04-Fibonacci</a>
+              </nav>
+            </div>
+          </div>
+        </div>
+      </section>
+      <section class="mdl-layout__tab-panel" id="scroll-tab-9">
         <div class="page-content">
           Soon.
         </div>
diff --git a/src/js/index.js b/src/js/index.js
@@ -34,3 +34,10 @@ export { default as HashTable } from './data-structures/hash-table';
 export { default as HashTableSeparateChaining } from './data-structures/hash-table-separate-chaining';
 export { default as HashTableLinearProbing } from './data-structures/hash-table-linear-probing';
 export { default as HashTableLinearProbingLazy } from './data-structures/hash-table-linear-probing-lazy';
+
+// chapter 08
+export { default as factorialIterative } from './others/factorial';
+export { default as factorial } from './others/factorial';
+export { default as fibonacci } from './others/fibonacci';
+export { default as fibonacciIterative } from './others/fibonacci';
+export { default as fibonacciMemoization } from './others/fibonacci';
diff --git a/src/js/others/factorial.js b/src/js/others/factorial.js
@@ -0,0 +1,20 @@
+export function factorialIterative(number) {
+  if (number < 0) {
+    return undefined;
+  }
+  let total = 1;
+  for (let n = number; n > 1; n--) {
+    total *= n;
+  }
+  return total;
+}
+
+export function factorial(n) {
+  if (n < 0) {
+    return undefined;
+  }
+  if (n === 1 || n === 0) {
+    return 1;
+  }
+  return n * factorial(n - 1);
+}
diff --git a/src/js/others/fibonacci.js b/src/js/others/fibonacci.js
@@ -0,0 +1,33 @@
+export function fibonacci(n) {
+  if (n < 1) {
+    return 0;
+  }
+  if (n <= 2) {
+    return 1;
+  }
+  return fibonacci(n - 1) + fibonacci(n - 2);
+}
+
+export function fibonacciIterative(n) {
+  if (n < 1) { return 0; }
+  let fibNMinus2 = 0;
+  let fibNMinus1 = 1;
+  let fibN = n;
+  for (let i = 2; i <= n; i++) {
+    fibN = fibNMinus1 + fibNMinus2;
+    fibNMinus2 = fibNMinus1;
+    fibNMinus1 = fibN;
+  }
+  return fibN;
+}
+
+export function fibonacciMemoization(n) {
+  if (n < 1) { return 0; }
+  const memo = [0, 1];
+  const fibonacciMem = num => {
+    if (memo[num] != null) { return memo[num]; }
+    memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2);
+    return (memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2));
+  };
+  return fibonacciMem(n);
+}
diff --git a/src/ts/index.ts b/src/ts/index.ts
@@ -1,4 +1,5 @@
 import * as _util from './util';
+export const util = _util;
 
 export { default as LinkedList } from './data-structures/linked-list';
 export { default as DoublyLinkedList } from './data-structures/doubly-linked-list';
@@ -12,7 +13,12 @@ export { default as HashTableSeparateChaining } from './data-structures/hash-tab
 export { default as HashTableLinearProbing } from './data-structures/hash-table-linear-probing';
 export { default as HashTableLinearProbingLazy } from './data-structures/hash-table-linear-probing-lazy';
 
-export const util = _util;
+// chapter 08
+export { factorialIterative as factorialIterative } from './others/factorial';
+export { factorial as factorial} from './others/factorial';
+export { fibonacci as fibonacci} from './others/fibonacci';
+export { fibonacciIterative as fibonacciIterative} from './others/fibonacci';
+export { fibonacciMemoization as fibonacciMemoization} from './others/fibonacci';
 
 
 /* import { hotPotato } from './others/hot-potato';
diff --git a/src/ts/others/factorial.ts b/src/ts/others/factorial.ts
@@ -0,0 +1,20 @@
+export function factorialIterative(number: number) {
+  if (number < 0) {
+    return undefined;
+  }
+  let total = 1;
+  for (let n = number; n > 1; n--) {
+    total  = total * n;
+  }
+  return total;
+}
+
+export function factorial(n: number): number {
+  if (n < 0) {
+    return undefined;
+  }
+  if (n === 1 || n === 0) {
+    return 1;
+  }
+  return n * factorial(n - 1);
+}
diff --git a/src/ts/others/fibonacci.ts b/src/ts/others/fibonacci.ts
@@ -0,0 +1,29 @@
+export function fibonacci(n: number): number {
+  if (n < 1) { return 0; } // {1}
+  if (n <= 2) { return 1; } // {2}
+  return fibonacci(n - 1) + fibonacci(n - 2); // {3}
+}
+
+export function fibonacciIterative(n: number) {
+  if (n < 1) { return 0; }
+  let fibNMinus2 = 0;
+  let fibNMinus1 = 1;
+  let fibN = n;
+  for (let i = 2; i <= n; i++) {
+    // n >= 2
+    fibN = fibNMinus1 + fibNMinus2; // f(n-1) + f(n-2)
+    fibNMinus2 = fibNMinus1;
+    fibNMinus1 = fibN;
+  }
+  return fibN;
+}
+
+export function fibonacciMemoization(n: number) {
+  if (n < 1) { return 0; }
+  const memo = [0, 1];
+  const fibonacciMem = (num: number): number => {
+    if (memo[num] != null) { return memo[num]; }
+    return (memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2));
+  };
+  return fibonacciMem(n);
+}
diff --git a/test/js/others/factorial.spec.js b/test/js/others/factorial.spec.js
@@ -0,0 +1,25 @@
+import 'mocha';
+import { expect } from 'chai';
+import { factorialIterative, factorial } from './../../../src/js/others/factorial';
+
+describe('Factorial', () => {
+  it('Iterative Factorial', () => {
+    expect(factorialIterative(-1)).to.equal(undefined);
+    expect(factorialIterative(0)).to.equal(1);
+    expect(factorialIterative(1)).to.equal(1);
+    expect(factorialIterative(2)).to.equal(2);
+    expect(factorialIterative(3)).to.equal(6);
+    expect(factorialIterative(4)).to.equal(24);
+    expect(factorialIterative(5)).to.equal(120);
+  });
+
+  it('Recursive Factorial', () => {
+    expect(factorial(-1)).to.equal(undefined);
+    expect(factorial(0)).to.equal(1);
+    expect(factorial(1)).to.equal(1);
+    expect(factorial(2)).to.equal(2);
+    expect(factorial(3)).to.equal(6);
+    expect(factorial(4)).to.equal(24);
+    expect(factorial(5)).to.equal(120);
+  });
+});
diff --git a/test/js/others/fibonacci.spec.js b/test/js/others/fibonacci.spec.js
@@ -0,0 +1,36 @@
+import 'mocha';
+import { expect } from 'chai';
+import {
+  fibonacci,
+  fibonacciIterative,
+  fibonacciMemoization
+} from '../../../src/js/others/fibonacci';
+
+describe('Fibonacci', () => {
+  it('Fibonacci Recursive', () => {
+    expect(fibonacci(-1)).to.equal(0);
+    expect(fibonacci(0)).to.equal(0);
+    expect(fibonacci(1)).to.equal(1);
+    expect(fibonacci(2)).to.equal(1);
+    expect(fibonacci(3)).to.equal(2);
+    expect(fibonacci(4)).to.equal(3);
+  });
+
+  it('Fibonacci Iterative', () => {
+    expect(fibonacciIterative(-1)).to.equal(0);
+    expect(fibonacciIterative(0)).to.equal(0);
+    expect(fibonacciIterative(1)).to.equal(1);
+    expect(fibonacciIterative(2)).to.equal(1);
+    expect(fibonacciIterative(3)).to.equal(2);
+    expect(fibonacciIterative(4)).to.equal(3);
+  });
+
+  it('Fibonacci with Memoization', () => {
+    expect(fibonacciMemoization(-1)).to.equal(0);
+    expect(fibonacciMemoization(0)).to.equal(0);
+    expect(fibonacciMemoization(1)).to.equal(1);
+    expect(fibonacciMemoization(2)).to.equal(1);
+    expect(fibonacciMemoization(3)).to.equal(2);
+    expect(fibonacciMemoization(4)).to.equal(3);
+  });
+});
diff --git a/test/ts/others/factorial.spec.ts b/test/ts/others/factorial.spec.ts
diff --git a/test/ts/others/fibonacci.spec.ts b/test/ts/others/fibonacci.spec.ts

Original file line number	Diff line number	Diff line change
`@@ -25,6 +25,7 @@`
`25`	`25`	`"import/prefer-default-export": 0,`
`26`	`26`	`"comma-dangle": 0,`
`27`	`27`	`"no-underscore-dangle": 0,`
`28`		`- "no-param-reassign": 0`
	`28`	`+ "no-param-reassign": 0,`
	`29`	`+ "no-return-assign": 0`
`29`	`30`	`}`
`30`	`31`	`}`