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chapter 08: [Recursion]
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‎.eslintrc.json

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"import/prefer-default-export": 0,
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"comma-dangle": 0,
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"no-underscore-dangle": 0,
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"no-param-reassign": 0
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"no-param-reassign": 0,
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"no-return-assign": 0
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}
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}

‎README.md

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@@ -17,6 +17,7 @@ Work in Progress.
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* 05: [LinkedLists](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter05)
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* 06: [Sets](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter06)
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* 07: [Dictionaries and Hashes](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter07)
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* 08: [Recursion](https://github.com/loiane/javascript-datastructures-algorithms/tree/third-edition/examples/chapter08)
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### Third Edition Updates
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‎examples/PacktDataStructuresAlgorithms.min.js

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‎examples/chapter08/01-IntroRecursion.html

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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8">
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<title></title>
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</head>
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<body>
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<script src="01-IntroRecursion.js"></script>
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</body>
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</html>

‎examples/chapter08/01-IntroRecursion.js

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// functions commented below - inifite loop
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/*
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function recursiveFunction(someParam) {
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recursiveFunction(someParam);
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}
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function recursiveFunction1(someParam) {
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recursiveFunction2(someParam);
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}
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function recursiveFunction2(someParam) {
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recursiveFunction1(someParam);
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}
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*/
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function understandRecursion(doIunderstandRecursion) {
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const recursionAnswer = confirm('Do you understand recursion?'); // function logic
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if (recursionAnswer === true) { // base case or stop point
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return true;
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}
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understandRecursion(recursionAnswer); // recursive call
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}
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understandRecursion(false);

‎examples/chapter08/02-Factorial.html

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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8">
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<title></title>
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</head>
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<body>
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<script src="02-Factorial.js"></script>
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</body>
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</html>

‎examples/chapter08/02-Factorial.js

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// @ts-check
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function factorialIterative(number) {
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if (number < 0) {
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return undefined;
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}
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let total = 1;
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for (let n = number; n > 1; n--) {
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total = total * n;
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}
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return total;
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}
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console.log('factorialIterative(5): ', factorialIterative(5));
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console.log('factorialIterative(3): ', factorialIterative(3));
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function factorial(n) {
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// console.trace();
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if (n === 1 || n === 0) {
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return 1;
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}
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return n * factorial(n - 1);
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}
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console.log('factorial(5): ', factorial(5));
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console.log('factorial(3): ', factorial(3));

‎examples/chapter08/03-JSCallStack.html

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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8">
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<title></title>
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</head>
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<body>
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<script src="03-JSCallStack.js"></script>
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</body>
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</html>

‎examples/chapter08/03-JSCallStack.js

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let i = 0;
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function recursiveFn() {
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i++;
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recursiveFn();
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}
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try {
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recursiveFn();
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} catch (ex) {
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console.log('i = ' + i + ' error: ' + ex);
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}

‎examples/chapter08/04-Fibonacci.html

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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="UTF-8">
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<title></title>
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</head>
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<body>
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<script src="04-Fibonacci.js"></script>
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</body>
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</html>

‎examples/chapter08/04-Fibonacci.js

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function fibonacci(n){
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if (n < 1) return 0; // {1}
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if (n <= 2) return 1; // {2}
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return fibonacci(n - 1) + fibonacci(n - 2); // {3}
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}
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console.log('fibonacci(2)', fibonacci(2));
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console.log('fibonacci(3)', fibonacci(3));
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console.log('fibonacci(4)', fibonacci(4));
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console.log('fibonacci(5)', fibonacci(5));
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function fibonacciIterative(n){
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let fibNMinus2 = 0;
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let fibNMinus1 = 1;
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let fibN = n;
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for (let i = 2; i <= n; i++) { // n >= 2
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fibN = fibNMinus1 + fibNMinus2; // f(n-1) + f(n-2)
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fibNMinus2 = fibNMinus1;
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fibNMinus1 = fibN;
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}
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return fibN;
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}
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console.log('fibonacciIterative(2)', fibonacciIterative(2));
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console.log('fibonacciIterative(3)', fibonacciIterative(3));
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console.log('fibonacciIterative(4)', fibonacciIterative(4));
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console.log('fibonacciIterative(5)', fibonacciIterative(5));
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function fibonacciMemoization(n) {
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const memo = [0, 1];
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const fibonacci = (n) => {
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if (memo[n] != null) return memo[n];
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return memo[n] = fibonacci(n - 1, memo) + fibonacci(n - 2, memo);
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};
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return fibonacci(n);
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}
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console.log('fibonacciMemoization(2)', fibonacciMemoization(2));
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console.log('fibonacciMemoization(3)', fibonacciMemoization(3));
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console.log('fibonacciMemoization(4)', fibonacciMemoization(4));
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console.log('fibonacciMemoization(5)', fibonacciMemoization(5));
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// https://jsperf.com/fibonacci-comparison-jsbook

‎examples/index.html

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<a href="#scroll-tab-5" class="mdl-layout__tab">05</a>
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<a href="#scroll-tab-6" class="mdl-layout__tab">06</a>
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<a href="#scroll-tab-7" class="mdl-layout__tab">07</a>
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<a href="#scroll-tab-8" class="mdl-layout__tab">08</a>
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</div>
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</header>
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<main class="mdl-layout__content">
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</div>
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</section>
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<section class="mdl-layout__tab-panel" id="scroll-tab-8">
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<div class="page-content">
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<div class="page-content mdl-layout--fixed-drawer">
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<div class="mdl-layout__drawer is-visible">
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<nav class="mdl-navigation">
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<a class="mdl-navigation__link" href="chapter08/01-IntroRecursion.html">01-IntroRecursion</a>
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<a class="mdl-navigation__link" href="chapter08/02-Factorial.html">02-Factorial</a>
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<a class="mdl-navigation__link" href="chapter08/03-JSCallStack.html">03-JSCallStack</a>
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<a class="mdl-navigation__link" href="chapter08/04-Fibonacci.html">04-Fibonacci</a>
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</nav>
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</div>
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</div>
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</div>
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</section>
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<section class="mdl-layout__tab-panel" id="scroll-tab-9">
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<div class="page-content">
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Soon.
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</div>

‎src/js/index.js

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export { default as HashTableSeparateChaining } from './data-structures/hash-table-separate-chaining';
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export { default as HashTableLinearProbing } from './data-structures/hash-table-linear-probing';
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export { default as HashTableLinearProbingLazy } from './data-structures/hash-table-linear-probing-lazy';
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// chapter 08
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export { default as factorialIterative } from './others/factorial';
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export { default as factorial } from './others/factorial';
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export { default as fibonacci } from './others/fibonacci';
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export { default as fibonacciIterative } from './others/fibonacci';
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export { default as fibonacciMemoization } from './others/fibonacci';

‎src/js/others/factorial.js

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export function factorialIterative(number) {
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if (number < 0) {
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return undefined;
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}
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let total = 1;
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for (let n = number; n > 1; n--) {
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total *= n;
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}
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return total;
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}
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export function factorial(n) {
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if (n < 0) {
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return undefined;
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}
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if (n === 1 || n === 0) {
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return 1;
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}
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return n * factorial(n - 1);
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}

‎src/js/others/fibonacci.js

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export function fibonacci(n) {
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if (n < 1) {
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return 0;
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}
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if (n <= 2) {
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return 1;
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}
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return fibonacci(n - 1) + fibonacci(n - 2);
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}
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export function fibonacciIterative(n) {
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if (n < 1) { return 0; }
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let fibNMinus2 = 0;
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let fibNMinus1 = 1;
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let fibN = n;
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for (let i = 2; i <= n; i++) {
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fibN = fibNMinus1 + fibNMinus2;
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fibNMinus2 = fibNMinus1;
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fibNMinus1 = fibN;
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}
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return fibN;
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}
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export function fibonacciMemoization(n) {
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if (n < 1) { return 0; }
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const memo = [0, 1];
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const fibonacciMem = num => {
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if (memo[num] != null) { return memo[num]; }
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memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2);
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return (memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2));
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};
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return fibonacciMem(n);
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}

‎src/ts/index.ts

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import * as _util from './util';
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export const util = _util;
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export { default as LinkedList } from './data-structures/linked-list';
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export { default as DoublyLinkedList } from './data-structures/doubly-linked-list';
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export { default as HashTableLinearProbing } from './data-structures/hash-table-linear-probing';
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export { default as HashTableLinearProbingLazy } from './data-structures/hash-table-linear-probing-lazy';
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15-
export const util = _util;
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// chapter 08
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export { factorialIterative as factorialIterative } from './others/factorial';
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export { factorial as factorial} from './others/factorial';
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export { fibonacci as fibonacci} from './others/fibonacci';
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export { fibonacciIterative as fibonacciIterative} from './others/fibonacci';
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export { fibonacciMemoization as fibonacciMemoization} from './others/fibonacci';
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/* import { hotPotato } from './others/hot-potato';

‎src/ts/others/factorial.ts

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export function factorialIterative(number: number) {
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if (number < 0) {
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return undefined;
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}
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let total = 1;
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for (let n = number; n > 1; n--) {
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total = total * n;
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}
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return total;
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}
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export function factorial(n: number): number {
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if (n < 0) {
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return undefined;
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}
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if (n === 1 || n === 0) {
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return 1;
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}
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return n * factorial(n - 1);
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}

‎src/ts/others/fibonacci.ts

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export function fibonacci(n: number): number {
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if (n < 1) { return 0; } // {1}
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if (n <= 2) { return 1; } // {2}
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return fibonacci(n - 1) + fibonacci(n - 2); // {3}
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}
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export function fibonacciIterative(n: number) {
8+
if (n < 1) { return 0; }
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let fibNMinus2 = 0;
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let fibNMinus1 = 1;
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let fibN = n;
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for (let i = 2; i <= n; i++) {
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// n >= 2
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fibN = fibNMinus1 + fibNMinus2; // f(n-1) + f(n-2)
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fibNMinus2 = fibNMinus1;
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fibNMinus1 = fibN;
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}
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return fibN;
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}
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export function fibonacciMemoization(n: number) {
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if (n < 1) { return 0; }
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const memo = [0, 1];
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const fibonacciMem = (num: number): number => {
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if (memo[num] != null) { return memo[num]; }
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return (memo[num] = fibonacciMem(num - 1) + fibonacciMem(num - 2));
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};
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return fibonacciMem(n);
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}

‎test/js/others/factorial.spec.js

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import 'mocha';
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import { expect } from 'chai';
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import { factorialIterative, factorial } from './../../../src/js/others/factorial';
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describe('Factorial', () => {
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it('Iterative Factorial', () => {
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expect(factorialIterative(-1)).to.equal(undefined);
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expect(factorialIterative(0)).to.equal(1);
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expect(factorialIterative(1)).to.equal(1);
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expect(factorialIterative(2)).to.equal(2);
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expect(factorialIterative(3)).to.equal(6);
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expect(factorialIterative(4)).to.equal(24);
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expect(factorialIterative(5)).to.equal(120);
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});
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it('Recursive Factorial', () => {
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expect(factorial(-1)).to.equal(undefined);
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expect(factorial(0)).to.equal(1);
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expect(factorial(1)).to.equal(1);
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expect(factorial(2)).to.equal(2);
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expect(factorial(3)).to.equal(6);
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expect(factorial(4)).to.equal(24);
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expect(factorial(5)).to.equal(120);
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});
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});

‎test/js/others/fibonacci.spec.js

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import 'mocha';
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import { expect } from 'chai';
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import {
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fibonacci,
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fibonacciIterative,
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fibonacciMemoization
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} from '../../../src/js/others/fibonacci';
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describe('Fibonacci', () => {
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it('Fibonacci Recursive', () => {
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expect(fibonacci(-1)).to.equal(0);
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expect(fibonacci(0)).to.equal(0);
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expect(fibonacci(1)).to.equal(1);
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expect(fibonacci(2)).to.equal(1);
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expect(fibonacci(3)).to.equal(2);
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expect(fibonacci(4)).to.equal(3);
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});
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it('Fibonacci Iterative', () => {
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expect(fibonacciIterative(-1)).to.equal(0);
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expect(fibonacciIterative(0)).to.equal(0);
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expect(fibonacciIterative(1)).to.equal(1);
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expect(fibonacciIterative(2)).to.equal(1);
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expect(fibonacciIterative(3)).to.equal(2);
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expect(fibonacciIterative(4)).to.equal(3);
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});
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it('Fibonacci with Memoization', () => {
29+
expect(fibonacciMemoization(-1)).to.equal(0);
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expect(fibonacciMemoization(0)).to.equal(0);
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expect(fibonacciMemoization(1)).to.equal(1);
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expect(fibonacciMemoization(2)).to.equal(1);
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expect(fibonacciMemoization(3)).to.equal(2);
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expect(fibonacciMemoization(4)).to.equal(3);
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});
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});

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