Fix #748 : Revise algorithm implementation so that it actually returns the combinations. Fix test (was not running, .mjs not matching Jest pattern) and work.

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/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]])
   })
 })