Merge pull request #1 from TheAlgorithms/master

update my fork

Author: josecarlosweb

Conversions/BinaryToDecimal.js

@@ -1,11 +1,14 @@
-function binaryToDeicmal (binaryNumber) {
+const binaryToDecimal = (binaryString) => {
   let decimalNumber = 0
-  const binaryDigits = binaryNumber.split('').reverse() // Splits the binary number into reversed single digits
+  const binaryDigits = binaryString.split('').reverse() // Splits the binary number into reversed single digits
   binaryDigits.forEach((binaryDigit, index) => {
     decimalNumber += binaryDigit * (Math.pow(2, index)) // Summation of all the decimal converted digits
   })
-  console.log(`Decimal of ${binaryNumber} is ${decimalNumber}`)
+  console.log(`Decimal of ${binaryString} is ${decimalNumber}`)
+  return decimalNumber
 }
 
-binaryToDeicmal('111001')
-binaryToDeicmal('101')
+(() => {
+  binaryToDecimal('111001')
+  binaryToDecimal('101')
+})()

DIRECTORY.md

@@ -34,7 +34,9 @@
     * [MaxHeap](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Heap/MaxHeap.js)
     * [MinPriorityQueue](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Heap/MinPriorityQueue.js)
   * Linked-List
+    * [CycleDetection](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Linked-List/CycleDetection.js)
     * [DoublyLinkedList](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Linked-List/DoublyLinkedList.js)
+    * [SingleCircularLinkedList](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Linked-List/SingleCircularLinkedList.js.js)
     * [SinglyLinkList](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Linked-List/SinglyLinkList.js)
   * Queue
     * [Queue](https://github.com/TheAlgorithms/Javascript/blob/master/Data-Structures/Queue/Queue.js)
@@ -50,6 +52,7 @@
   * [ClimbingStairs](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/ClimbingStairs.js)
   * [CoinChange](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/CoinChange.js)
   * [EditDistance](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/EditDistance.js)
+  * [FibonacciNumber](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/FibonacciNumber.js)
   * [KadaneAlgo](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/KadaneAlgo.js)
   * [LevenshteinDistance](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/LevenshteinDistance.js)
   * [LongestCommonSubsequence](https://github.com/TheAlgorithms/Javascript/blob/master/Dynamic-Programming/LongestCommonSubsequence.js)
@@ -87,6 +90,7 @@
   * [FindHcf](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/FindHcf.js)
   * [FindLcm](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/FindLcm.js)
   * [GridGet](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/GridGet.js)
+  * [MeanSquareError](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/MeanSquareError.js)
   * [ModularBinaryExponentiationRecursive](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/ModularBinaryExponentiationRecursive.js)
   * [Palindrome](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/Palindrome.js)
   * [PascalTriangle](https://github.com/TheAlgorithms/Javascript/blob/master/Maths/PascalTriangle.js)
@@ -101,6 +105,7 @@
 
 ## Recursive
   * [EucledianGCD](https://github.com/TheAlgorithms/Javascript/blob/master/Recursive/EucledianGCD.js)
+  * [FibonacciNumberRecursive](https://github.com/TheAlgorithms/Javascript/blob/master/Recursive/FibonacciNumberRecursive.js)
   * [TowerOfHanoi](https://github.com/TheAlgorithms/Javascript/blob/master/Recursive/TowerOfHanoi.js)
 
 ## Search
@@ -130,6 +135,7 @@
   * [QuickSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/QuickSort.js)
   * [RadixSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/RadixSort.js)
   * [SelectionSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/SelectionSort.js)
+  * [SelectionSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/SelectionSort.test.js)
   * [ShellSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/ShellSort.js)
   * [TimSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/TimSort.js)
   * [TopologicalSort](https://github.com/TheAlgorithms/Javascript/blob/master/Sorts/TopologicalSort.js)
@@ -141,6 +147,8 @@
   * [CheckPalindrome](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckPalindrome.js)
   * [CheckPalindrome](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckPalindrome.test.js)
   * [CheckRearrangePalindrome](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckRearrangePalindrome.js)
+  * [CheckWordOccurrence](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckWordOccurrence.js)
+  * [CheckWordOcurrence](https://github.com/TheAlgorithms/Javascript/blob/master/String/CheckWordOcurrence.test.js)
   * [PatternMatching](https://github.com/TheAlgorithms/Javascript/blob/master/String/PatternMatching.js)
   * [PatternMatching](https://github.com/TheAlgorithms/Javascript/blob/master/String/PatternMatching.test.js)
   * [ReverseString](https://github.com/TheAlgorithms/Javascript/blob/master/String/ReverseString.js)

Data-Structures/Linked-List/CycleDetection.js

@@ -0,0 +1,32 @@
+/**
+ * A LinkedList based solution for Detect a Cycle in a list
+ * https://en.wikipedia.org/wiki/Cycle_detection
+ */
+
+function main () {
+  /*
+  Problem Statement:
+  Given head, the head of a linked list, determine if the linked list has a cycle in it.
+
+  Note:
+  * While Solving the problem in given link below, don't use main() function.
+  * Just use only the code inside main() function.
+  * The purpose of using main() function here is to aviod global variables.
+
+  Link for the Problem: https://leetcode.com/problems/linked-list-cycle/
+  */
+  const head = '' // Reference to head is given in the problem. So please ignore this line
+  let fast = head
+  let slow = head
+
+  while (fast != null && fast.next != null && slow != null) {
+    fast = fast.next.next
+    slow = slow.next
+    if (fast === slow) {
+      return true
+    }
+  }
+  return false
+}
+
+main()

Data-Structures/Linked-List/SingleCircularLinkedList.js.js

@@ -0,0 +1,97 @@
+class Node {
+  constructor (data, next = null) {
+    this.data = data
+    this.next = next
+  }
+}
+
+class SinglyCircularLinkedList {
+  constructor () {
+    this.head = null
+    this.size = 0
+  }
+
+  insert (data) {
+    const node = new Node(data)
+
+    if (!this.head) {
+      node.next = node
+      this.head = node
+      this.size++
+    } else {
+      node.next = this.head
+
+      let current = this.head
+
+      while (current.next.data !== this.head.data) {
+        current = current.next
+      }
+
+      current.next = node
+      this.size++
+    }
+  }
+
+  insertAt (index, data) {
+    const node = new Node(data)
+
+    if (index < 0 || index > this.size) return
+
+    if (index === 0) {
+      this.head = node
+      this.size = 1
+      return
+    }
+
+    let previous
+    let count = 0
+    let current = this.head
+
+    while (count < index) {
+      previous = current
+      current = current.next
+      count++
+    }
+
+    node.next = current
+    previous.next = node
+    this.size++
+  }
+
+  remove () {
+    if (!this.head) return
+
+    let prev
+    let current = this.head
+
+    while (current.next !== this.head) {
+      prev = current
+      current = current.next
+    }
+
+    prev.next = this.head
+    this.size--
+  }
+
+  printData () {
+    let count = 0
+    let current = this.head
+
+    while (current !== null && count !== this.size) {
+      console.log(current.data + '\n')
+      current = current.next
+      count++
+    }
+  }
+}
+
+const ll = new SinglyCircularLinkedList()
+
+ll.insert(10)
+ll.insert(20)
+ll.insert(30)
+ll.insert(40)
+ll.insert(50)
+ll.insertAt(5, 60)
+ll.remove(5)
+ll.printData()

Dynamic-Programming/FibonacciNumber.js

@@ -0,0 +1,18 @@
+//  https://en.wikipedia.org/wiki/Fibonacci_number
+
+const fibonacci = (N) => {
+  // creating array to store values
+  const memo = new Array(N + 1)
+  memo[0] = 0
+  memo[1] = 1
+  for (let i = 2; i <= N; i++) {
+    memo[i] = memo[i - 1] + memo[i - 2]
+  }
+  return memo[N]
+}
+
+// testing
+(() => {
+  const number = 5
+  console.log(number + 'th Fibonacci number is ' + fibonacci(number))
+})()

Maths/MeanSquareError.js

@@ -0,0 +1,26 @@
+// Wikipedia: https://en.wikipedia.org/wiki/Mean_squared_error
+
+const meanSquaredError = (predicted, expected) => {
+  if (!Array.isArray(predicted) || !Array.isArray(expected)) {
+    throw new TypeError('Argument must be an Array')
+  }
+
+  if (predicted.length !== expected.length) {
+    throw new TypeError('The two lists must be of equal length')
+  }
+
+  let err = 0
+
+  for (let i = 0; i < expected.length; i++) {
+    err += (expected[i] - predicted[i]) ** 2
+  }
+
+  return err / expected.length
+}
+
+// testing
+(() => {
+  console.log(meanSquaredError([1, 2, 3, 4], [1, 2, 3, 4]) === 0)
+  console.log(meanSquaredError([4, 3, 2, 1], [1, 2, 3, 4]) === 5)
+  console.log(meanSquaredError([2, 0, 2, 0], [0, 0, 0, 0]) === 3)
+})()

Recursive/FibonacciNumberRecursive.js

@@ -0,0 +1,13 @@
+//  https://en.wikipedia.org/wiki/Fibonacci_number
+
+const fibonacci = (N) => {
+  if (N === 0 || N === 1) return N
+
+  return fibonacci(N - 2) + fibonacci(N - 1)
+}
+
+// testing
+(() => {
+  const number = 5
+  console.log(number + 'th Fibonacci number is ' + fibonacci(number))
+})()

Sorts/SelectionSort.js

@@ -8,29 +8,43 @@
  *from the unsorted subarray is picked and moved to the sorted subarray.
  */
 
-function selectionSort (items) {
-  var length = items.length
-  for (var i = 0; i < length - 1; i++) {
+const selectionSort = (list) => {
+  if (!Array.isArray(list)) {
+    throw new TypeError('Given input is not an array')
+  }
+  const items = [...list] // We don't want to modify the original array
+  const length = items.length
+  for (let i = 0; i < length - 1; i++) {
+    if (typeof items[i] !== 'number') {
+      throw new TypeError('One of the items in your array is not a number')
+    }
     // Number of passes
-    var min = i // min holds the current minimum number position for each pass; i holds the Initial min number
-    for (var j = i + 1; j < length; j++) { // Note that j = i + 1 as we only need to go through unsorted array
+    let min = i // min holds the current minimum number position for each pass; i holds the Initial min number
+    for (let j = i + 1; j < length; j++) { // Note that j = i + 1 as we only need to go through unsorted array
       if (items[j] < items[min]) { // Compare the numbers
         min = j // Change the current min number position if a smaller num is found
       }
     }
     if (min !== i) {
       // After each pass, if the current min num != initial min num, exchange the position.
       // Swap the numbers
-      [items[i], items[min]] = [items[min], [items[i]]]
+      [items[i], items[min]] = [items[min], items[i]]
     }
   }
+  return items
 }
 
-// Implementation of Selection Sort
+/* Implementation of Selection Sort
+
+(() => {
+  let array = [5, 6, 7, 8, 1, 2, 12, 14]
+  // Array before Sort
+  console.log(array)
+  array = selectionSort(array)
+  // Array after sort
+  console.log(array)
+})()
+
+*/
 
-var ar = [5, 6, 7, 8, 1, 2, 12, 14]
-// Array before Sort
-console.log(ar)
-selectionSort(ar)
-// Array after sort
-console.log(ar)
+export { selectionSort }

Sorts/SelectionSort.test.js

@@ -0,0 +1,22 @@
+import { selectionSort } from './SelectionSort'
+
+describe('selectionSort', () => {
+  it('expects to return the array sorted in ascending order', () => {
+    var toSort = [5, 6, 7, 8, 1, 2, 12, 14]
+    const expected = [1, 2, 5, 6, 7, 8, 12, 14]
+
+    expect(selectionSort(toSort)).toEqual(expected)
+  })
+
+  it('expects to throw if it is not a valid array', () => {
+    expect(() => selectionSort('abc')).toThrow('Given input is not an array')
+    expect(() => selectionSort(123)).toThrow('Given input is not an array')
+    expect(() => selectionSort({})).toThrow('Given input is not an array')
+    expect(() => selectionSort(null)).toThrow('Given input is not an array')
+    expect(() => selectionSort()).toThrow('Given input is not an array')
+  })
+
+  it('expects to throw if one of the elements in the array is not a number', () => {
+    expect(() => selectionSort([1, 'x', 2])).toThrow('One of the items in your array is not a number')
+  })
+})

String/CheckWordOccurrence.js

@@ -0,0 +1,25 @@
+/**
+  * Check and count occurrence of each word in a string
+  * Inputs a String eg. Madonna and Boolean
+  **/
+
+const checkWordOccurrence = (str, isCaseSensitive = false) => {
+  if (typeof str !== 'string') {
+    throw new TypeError('The first param should be a string')
+  }
+  if (typeof isCaseSensitive !== 'boolean') {
+    throw new TypeError('The second param should be a boolean')
+  }
+
+  const result = {}
+  if (str.length > 0) {
+    for (let i = 0; i < str.length; i++) {
+      const word = isCaseSensitive ? str[i] : str[i].toUpperCase()
+      if (/\s/.test(word)) continue
+      result[word] = (!result[word]) ? 1 : result[word] + 1
+    }
+  }
+
+  return result
+}
+export { checkWordOccurrence }