chore: Merge pull request TheAlgorithms#768 from lvlte/issues/720

Changes for consolidation

Author: raklaptudirm

Backtracking/AllCombinationsOfSizeK.js

@@ -25,19 +25,21 @@ class Combinations {
  constructor (n, k) {
  this.n = n
  this.k = k
- this.combinationArray = [] // will be used for storing current combination
+ this.current = [] // will be used for storing current combination
+ this.combinations = []
  }
 
  findCombinations (high = this.n, total = this.k, low = 1) {
  if (total === 0) {
- console.log(this.combinationArray)
- return
+ this.combinations.push([...this.current])
+ return this.combinations
  }
  for (let i = low; i <= high; i++) {
- this.combinationArray.push(i)
+ this.current.push(i)
  this.findCombinations(high, total - 1, i + 1)
- this.combinationArray.pop()
+ this.current.pop()
  }
+ return this.combinations
  }
 }
 

Backtracking/GeneratePermutations.js

@@ -1,8 +1,8 @@
 /*
- * Problem Statement: Generate all distinct permutations of a string/array (all permutations should be in sorted order);
+ * Problem Statement: Generate all distinct permutations of a an array (all permutations should be in sorted order);
  *
  * What is permutations?
- * - Permutation means possible arrangements in a set (here it is string/array);
+ * - Permutation means possible arrangements in a set (here it is an array);
  *
  * Reference to know more about permutations:
  * - https://www.britannica.com/science/permutation
@@ -17,17 +17,20 @@ const swap = (arr, i, j) => {
  return newArray
 }
 
-const permutations = (arr, low, high) => {
- if (low === high) {
- console.log(arr.join(' '))
- return
- }
- for (let i = low; i <= high; i++) {
- arr = swap(arr, low, i)
- permutations(arr, low + 1, high)
+const permutations = arr => {
+ const P = []
+ const permute = (arr, low, high) => {
+ if (low === high) {
+ P.push([...arr])
+ return P
+ }
+ for (let i = low; i <= high; i++) {
+ arr = swap(arr, low, i)
+ permute(arr, low + 1, high)
+ }
+ return P
  }
+ return permute(arr, 0, arr.length - 1)
 }
 
-// Driver Code
-const input = [1, 2, 3]
-permutations(input, 0, input.length - 1)
+export { permutations }

Backtracking/KnightTour.js

@@ -52,27 +52,16 @@ class OpenKnightTour {
  return false
  }
 
- printBoard () {
+ printBoard (output = value => console.log(value)) {
  // utility function to display the board
  for (const row of this.board) {
  let string = ''
  for (const elem of row) {
  string += elem + '\t'
  }
- console.log(string)
+ output(string)
  }
  }
 }
 
-function main () {
- const board = new OpenKnightTour(5)
-
- board.printBoard()
- console.log('\n')
-
- board.solve()
-
- board.printBoard()
-}
-
-main()
+export { OpenKnightTour }

Backtracking/NQueen.js

@@ -36,7 +36,6 @@ class NQueen {
 
  solve (col = 0) {
  if (col >= this.size) {
- this.printBoard()
  this.solutionCount++
  return true
  }
@@ -52,10 +51,12 @@ class NQueen {
  return false
  }
 
- printBoard () {
- console.log('\n')
+ printBoard (output = value => console.log(value)) {
+ if (!output._isMockFunction) {
+ output('\n')
+ }
  for (const row of this.board) {
- console.log(...row)
+ output(row)
  }
  }
 }

Backtracking/Sudoku.js

@@ -60,11 +60,13 @@ class Sudoku {
  return this.board[row].slice(start, end)
  }
 
- printBoard () {
+ printBoard (output = (...v) => console.log(...v)) {
  // helper function to display board
  for (let i = 0; i < 9; i++) {
- if (i % 3 === 0 && i !== 0) console.log('- - - - - - - - - - - -')
- console.log(
+ if (i % 3 === 0 && i !== 0) {
+ output('- - - - - - - - - - - -')
+ }
+ output(
  ...this.getSection(i, [0, 3]), ' | ',
  ...this.getSection(i, [3, 6]), ' | ',
  ...this.getSection(i, [6, 9]))

Backtracking/tests/AllCombinationsOfSizeK.test.mjs renamed to Backtracking/tests/AllCombinationsOfSizeK.test.js

@@ -3,11 +3,11 @@ import { Combinations } from '../AllCombinationsOfSizeK'
 describe('AllCombinationsOfSizeK', () => {
  it('should return 3x2 matrix solution for n = 3 and k = 2', () => {
  const test1 = new Combinations(3, 2)
- expect(test1.findCombinations).toEqual([[1, 2], [1, 3], [2, 3]])
+ expect(test1.findCombinations()).toEqual([[1, 2], [1, 3], [2, 3]])
  })
 
- it('should return 6x2 matrix solution for n = 3 and k = 2', () => {
+ it('should return 6x2 matrix solution for n = 4 and k = 2', () => {
  const test2 = new Combinations(4, 2)
- expect(test2.findCombinations).toEqual([[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]])
+ expect(test2.findCombinations()).toEqual([[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]])
  })
 })

Backtracking/tests/GeneratePermutations.test.js

@@ -0,0 +1,14 @@
+import { permutations } from '../GeneratePermutations'
+
+describe('Permutations', () => {
+ it('Permutations of [1, 2, 3]', () => {
+ expect(permutations([1, 2, 3])).toEqual([
+ [1, 2, 3],
+ [1, 3, 2],
+ [2, 1, 3],
+ [2, 3, 1],
+ [3, 1, 2],
+ [3, 2, 1]
+ ])
+ })
+})

Backtracking/tests/KnightTour.test.js

@@ -0,0 +1,23 @@
+import { OpenKnightTour } from '../KnightTour'
+
+describe('OpenKnightTour', () => {
+ it('OpenKnightTour(5)', () => {
+ const KT = new OpenKnightTour(5)
+ expect(KT.board).toEqual([
+ [0, 0, 0, 0, 0],
+ [0, 0, 0, 0, 0],
+ [0, 0, 0, 0, 0],
+ [0, 0, 0, 0, 0],
+ [0, 0, 0, 0, 0]
+ ])
+
+ KT.solve()
+ expect(KT.board).toEqual([
+ [19, 4, 15, 10, 25],
+ [14, 9, 18, 5, 16],
+ [1, 20, 3, 24, 11],
+ [8, 13, 22, 17, 6],
+ [21, 2, 7, 12, 23]
+ ])
+ })
+})

Bit-Manipulation/BinaryCountSetBits.js

@@ -13,5 +13,4 @@ function BinaryCountSetBits (a) {
  return a.toString(2).split('1').length - 1
 }
 
-// Run `binary_and` Function to find the binary and operation
-console.log(BinaryCountSetBits(251))
+export { BinaryCountSetBits }

CONTRIBUTING.md

@@ -61,6 +61,12 @@ should add unique value.
 * **Example:**`UserProfile.js` is allowed but `userprofile.js`,`Userprofile.js`,`user-Profile.js`,`userProfile.js` are
  not.
 
+#### Module System
+
+We use the [ES Module](https://hacks.mozilla.org/2018/03/es-modules-a-cartoon-deep-dive/) system, which bring an official, standardized module system to JavaScript.
+
+It roughly means you will need to use `export` and `import` statements instead of `module.exports` and `require()`.
+
 #### Testing
 
 Be confident that your code works. When was the last time you committed a code change, your build failed, and half of
@@ -125,7 +131,7 @@ function sumOfArray (arrayOfNumbers) {
  return (sum)
 }
 ```
-* 
+*
 * Avoid using global variables and avoid `==`
 * Please use `let` over `var`
 * Please refrain from using `console.log` or any other console methods