- refactor SelectionSort to extend GenericSort

- refactor InsertionSort to extend GenericSort
- removed duplicated sorting tests

Author: Isaac Ramirez

src/algorithms/insertion-sort/insertion-sort.js

@@ -1,69 +1,13 @@
-const { StdOut } = require('../../libs')
-const { defaultComparator } = require('../../common')
+const { GenericSort } = require('../../abstracts')
 
 /**
  * Insertion
+ * @augments GenericSort
  * @classdesc Insertion Sort Algorithm.
  * @see p. 245, 251
  * @see {@link https://algs4.cs.princeton.edu/code/edu/princeton/cs/algs4/Insertion.java.html}
  */
-class Insertion {
-  /**
-   * Returns whether `a` is less than `b`
-   * based on a comparing function.
-   * @param {*} a Comparable object `a`
-   * @param {*} b Comparable object `b`
-   * @param {function} comparator A comparing function that
-   * returns -1 when `a` is less than `b`,
-   * returns 1 when `a` is greater than `b` or
-   * returns 0 when `a` is equal to `b`.
-   */
-  static less (a, b, comparator = defaultComparator) {
-    return comparator(a, b) < 0
-  }
-
-  /**
-   * Interchanges the values located in indexes `i` and `j`
-   * for the given `array`.
-   * @param {[*]} array Array of values.
-   * @param {number} i Index 1
-   * @param {number} j Index 2
-   */
-  static exchange (array, i, j) {
-    const temp = array[i]
-
-    array[i] = array[j]
-    array[j] = temp
-  }
-
-  /**
-   * Returns `true` if the provided array is sorted,
-   * `false` otherwise.
-   * @param {[*]} array Array of values
-   * @param {function} comparator A comparing function that
-   * returns -1 when `a` is less than `b`,
-   * returns 1 when `a` is greater than `b` or
-   * returns 0 when `a` is equal to `b`.
-   */
-  static isSorted (array, comparator = defaultComparator) {
-    for (let i = 1; i < array.length; i++) {
-      if (this.less(array[i], array[i - 1], comparator)) {
-        return false
-      }
-    }
-
-    return true
-  }
-
-  /**
-   * A function that prints to the StdOut
-   * the contents of the `array` provided.
-   * @param {[*]} array Array of values.
-   */
-  static show (array) {
-    StdOut.println(array.join(' '))
-  }
-
+class Insertion extends GenericSort {
   /**
    * Sorts the `array` using the Insertion Sort algorithm.
    * @param {[*]} array Array of values.
@@ -72,7 +16,7 @@ class Insertion {
    * returns 1 when `a` is greater than `b` or
    * returns 0 when `a` is equal to `b`.
    */
-  static sort (array, comparator = defaultComparator) {
+  static sort (array, comparator) {
     const n = array.length
 
     for (let i = 1; i < n; i++) {

src/algorithms/insertion-sort/insertion-sort.spec.js

@@ -1,7 +1,6 @@
 const Insertion = require('./insertion-sort')
 const { newArrayOf } = require('../../utils')
 const { StdRandom } = require('../../libs')
-const { defaultComparator: comparator } = require('../../common')
 
 describe('Unit Tests: Insertion Sort Algorithm', () => {
   beforeEach(() => {
@@ -11,97 +10,7 @@ describe('Unit Tests: Insertion Sort Algorithm', () => {
     this.allEqualArray = [9, 9, 9, 9, 9, 9, 9, 9, 9, 9]
   })
 
-  describe('static less method', () => {
-    it('should return true if a is less than b', () => {
-      const a = 1
-      const b = 2
-
-      expect(Insertion.less(a, b, comparator)).toBe(true)
-    })
-
-    it('should return false if a is greater than b', () => {
-      const a = 2
-      const b = 1
-
-      expect(Insertion.less(a, b, comparator)).toBe(false)
-    })
-
-    it('should return false if a is equal to b', () => {
-      const a = 1
-      const b = 1
-
-      expect(Insertion.less(a, b, comparator)).toBe(false)
-    })
-
-    it('should have a defaultComparator function', () => {
-      expect(Insertion.less(1, 10)).toBe(true)
-      expect(Insertion.less(1, 1)).toBe(false)
-      expect(Insertion.less(10, 1)).toBe(false)
-    })
-  })
-
-  describe('static exchange method', () => {
-    it('should interchange the values of the two given indexes in the array', () => {
-      const array = [5, 6, 7]
-      const expectedArray = [7, 6, 5]
-
-      Insertion.exchange(array, 0, 2)
-
-      expect(array).toEqual(expectedArray)
-    })
-  })
-
-  describe('static isSorted method', () => {
-    it('should return true if an array is sorted', () => {
-      expect(Insertion.isSorted(this.orderedArray)).toBe(true)
-      expect(Insertion.isSorted(this.allEqualArray)).toBe(true)
-    })
-
-    it('should return false if the array is not sorted', () => {
-      expect(Insertion.isSorted(this.unorderedArray)).toBe(false)
-      expect(Insertion.isSorted(this.reversedArray)).toBe(false)
-    })
-
-    it('should accept a comparator function', () => {
-      const orderedArray = ['A', 'B', 'C']
-      const unorderedArray = ['Z', 'X', 'Y']
-
-      expect(Insertion.isSorted(orderedArray, comparator)).toBe(true)
-      expect(Insertion.isSorted(unorderedArray, comparator)).toBe(false)
-    })
-
-    it('should return true for a sorted big array', () => {
-      const n = 1000000 // a million!
-      const array = newArrayOf(n, i => i) // from 0 to 999999
-
-      expect(Insertion.isSorted(array)).toBeTrue()
-    })
-
-    it('should return false for a random big array', () => {
-      const n = 1000000 // a million!
-      const array = newArrayOf(n, i => i) // from 0 to 999999
-      array[array.length - 1] = 0 // change last number to be 0
-
-      expect(Insertion.isSorted(array)).toBeFalse()
-    })
-  })
-
-  describe('static show method', () => {
-    it('should be a function', () => {
-      // I could test the call to StdOut, but I don't want to.
-      expect(Insertion.show).toBeInstanceOf(Function)
-    })
-  })
-
   describe('static sort method', () => {
-    it('should sort a unordered array', () => {
-      const expectedArray = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
-
-      Insertion.sort(this.unorderedArray)
-
-      expect(this.unorderedArray).toEqual(expectedArray)
-    })
-
     it('should sort an ordered array', () => {
       const expectedArray = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
 
@@ -118,6 +27,14 @@ describe('Unit Tests: Insertion Sort Algorithm', () => {
       expect(this.reversedArray).toEqual(expectedArray)
     })
 
+    it('should sort a unordered array', () => {
+      const expectedArray = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+
+      Insertion.sort(this.unorderedArray)
+
+      expect(this.unorderedArray).toEqual(expectedArray)
+    })
+
     it('should sort an array with all the values to be equal', () => {
       const expectedArray = [9, 9, 9, 9, 9, 9, 9, 9, 9, 9]
 

src/algorithms/selection-sort/selection-sort.js

@@ -1,69 +1,13 @@
-const { StdOut } = require('../../libs')
-const { defaultComparator } = require('../../common')
+const { GenericSort } = require('../../abstracts')
 
 /**
  * Selection
+ * @augments GenericSort
  * @classdesc Selection Sort Algorithm.
  * @see p. 245, 249
  * @see {@link https://algs4.cs.princeton.edu/code/edu/princeton/cs/algs4/Selection.java.html}
  */
-class Selection {
-  /**
-   * Returns whether `a` is less than `b`
-   * based on a comparing function.
-   * @param {*} a Comparable object `a`
-   * @param {*} b Comparable object `b`
-   * @param {function} comparator A comparing function that
-   * returns -1 when `a` is less than `b`,
-   * returns 1 when `a` is greater than `b` or
-   * returns 0 when `a` is equal to `b`.
-   */
-  static less (a, b, comparator = defaultComparator) {
-    return comparator(a, b) < 0
-  }
-
-  /**
-   * Interchanges the values located in indexes `i` and `j`
-   * for the given `array`.
-   * @param {[*]} array Array of values.
-   * @param {number} i Index 1
-   * @param {number} j Index 2
-   */
-  static exchange (array, i, j) {
-    const temp = array[i]
-
-    array[i] = array[j]
-    array[j] = temp
-  }
-
-  /**
-   * Returns `true` if the provided array is sorted,
-   * `false` otherwise.
-   * @param {[*]} array Array of values
-   * @param {function} comparator A comparing function that
-   * returns -1 when `a` is less than `b`,
-   * returns 1 when `a` is greater than `b` or
-   * returns 0 when `a` is equal to `b`.
-   */
-  static isSorted (array, comparator = defaultComparator) {
-    for (let i = 1; i < array.length; i++) {
-      if (this.less(array[i], array[i - 1], comparator)) {
-        return false
-      }
-    }
-
-    return true
-  }
-
-  /**
-   * A function that prints to the StdOut
-   * the contents of the `array` provided.
-   * @param {[*]} array Array of values.
-   */
-  static show (array) {
-    StdOut.println(array.join(' '))
-  }
-
+class Selection extends GenericSort {
   /**
    * Sorts the `array` using the Selection Sort algorithm.
    * @param {[*]} array Array of values.
@@ -72,7 +16,7 @@ class Selection {
    * returns 1 when `a` is greater than `b` or
    * returns 0 when `a` is equal to `b`.
    */
-  static sort (array, comparator = defaultComparator) {
+  static sort (array, comparator) {
     const n = array.length
 
     for (let i = 0; i < n; i++) {