added Bidirectional Conditional Insertion Sort

README.md

@@ -83,6 +83,7 @@ a set of rules that precisely define a sequence of operations.
   * [Shellsort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/shell-sort)
   * [Counting Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/counting-sort)
   * [Radix Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/radix-sort)
+  * [Bidirectional Conditional Insertion Sort](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/sorting/bidirectional-conditional-insertion-sort)
 * **Trees**
   * [Depth-First Search](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/tree/depth-first-search) (DFS)
   * [Breadth-First Search](https://github.com/trekhleb/javascript-algorithms/tree/master/src/algorithms/tree/breadth-first-search) (BFS)

src/algorithms/sorting/bidirectional-conditional-insertion-sort/BCIS.js

@@ -0,0 +1,136 @@
+import Sort from '../Sort';
+import Comparator from '../../../utils/comparator/Comparator';
+export default class BCIS extends Sort {
+   /**
+   * @param {Object[]} _array array to be swapped
+   * @param {number} a index a to be swapped with index b
+   * @param {number} b index b to be swapped with index a
+   */
+  static SWAP(_array = [], i, j) {
+    const temp = _array[i];
+    _array[i] = _array[j];
+    _array[j] = temp;
+  } // end SWAP
+  /**
+   * @param {Object[]} _array 
+   * @param {*} _current_item 
+   * @param {number} SR 
+   * @param {number} right 
+   */
+  static INSRIGHT(_array, _current_item, SR, right, comp) {
+    let j = SR;
+    do {
+      _array[j - 1] = _array[j];
+      j = j + 1;
+    }
+    while (comp.lessThanOrEqual(j,right) && comp.greaterThan(_current_item, _array[j]));
+    _array[j - 1] = _current_item;
+  } // end INSRIGHT
+  /**
+   * 
+   * @param {Object[]} _array 
+   * @param {*} _current_item 
+   * @param {number} SL 
+   * @param {number} left 
+   */
+  static INSLEFT(_array, _current_item, SL, left, comp) {
+    let j = SL;
+    do {
+      _array[j + 1] = _array[j];
+      j = j - 1;
+    }
+    while (comp.greaterThanOrEqual(j,left) && comp.lessThan(_current_item, _array[j]));
+    _array[j + 1] = _current_item;
+  } // end INSLEFT
+  /**
+   * @param {Object[]} _array 
+   * @param {number} SL 
+   * @param {number} SR 
+   */
+  static ISEQUAL(_array, SL, SR, comp) {
+    for (let k = SL + 1; k <= SR - 1; k++) {
+      if (comp.compare(_array[k],_array[SL] !== 0)) {
+        this.SWAP(_array, k, SL);
+        return k;
+      } // end if
+    } // end for
+    return -1;
+  } // end ISEQUAL
+  /**
+   * @param {Object[]} _array array to be sorted
+   * @param {number} left index of left sorted array 
+   * @param {number} right index of right sorted array
+   */
+  static Sort(_array = [], left = null, right = null) {
+    let SL = left;
+    let SR = right;
+    let i;
+    let comp = new Comparator(function(a,b){
+        let x = a;
+        let y = b;
+        if(typeof a === "string"){
+            x = a.length;
+        }
+        if(typeof b === "string"){
+            y = b.length;
+        }
+        if (x === y) {
+            return 0;
+        }          
+        return x < y ? -1 : 1;
+    })
+
+    do {
+      let calc = Math.round(SL + (SR - SL) / 2);
+      this.SWAP(_array, SR, calc);
+      if (comp.equal(_array[SL],_array[SR])) {
+        if (this.ISEQUAL(_array, SL, SR, comp) === -1) {
+          return;
+        } // end if
+      } // end if
+      if (comp.greaterThan(_array[SL],_array[SR])) {
+        this.SWAP(_array, SL, SR);
+      } // end if
+      if (SR - SL >= 100) {
+        for (i = (SL + 1); i <= parseInt(Math.pow(SR - SL, 0.5)); i++) {
+          if (comp.lessThan(_array[SR], _array[i])) {
+            this.SWAP(_array, SR, i);
+          }
+          else if (comp.greaterThan(_array[SL], _array[i])) {
+            this.SWAP(_array, SL, i);
+          } // end if
+        } // end for
+      }
+      else {
+        i = SL + 1;
+      } // end if
+      let LC = _array[SL];
+      let RC = _array[SR];
+      do {
+        let _current_item = _array[i];
+        if (comp.greaterThan(_current_item,RC)) {
+          _array[i] = _array[SR - 1];
+          this.INSRIGHT(_array, _current_item, SR, right, comp);
+          SR--;
+        }
+        else if (comp.lessThan(_current_item, LC)) {
+          _array[i] = _array[SL + 1];
+          this.INSLEFT(_array, _current_item, SL, left, comp);
+          SL++; i++;
+        }
+        else {
+          i++;
+        } // end if
+      }
+      while (i < SR)
+      SL++;
+      SR--;
+    }
+    while (SL < SR)
+  } // end Sort
+  sort(array) {
+    if(array.length === 0) return [];
+    BCIS.Sort(array, 0, array.length - 1);
+    return array;
+  } // end sort
+}

src/algorithms/sorting/bidirectional-conditional-insertion-sort/README.md

@@ -0,0 +1,8 @@
+# Bidirectional Conditional Insertion Sort
+
+This is a javascript implementation of the Bidirectional Conditional Insertion Sort algorithm published by Future Computer Systems Volume 71, June 2017, Pages 102-112. Read about it here: 
+
+[Journal](https://www.sciencedirect.com/science/article/pii/S0167739X17301711?via%3Dihub)
+
+## References
+- [Science Direct](https://www.sciencedirect.com/science/article/pii/S0167739X17301711?via%3Dihub)

src/algorithms/sorting/bidirectional-conditional-insertion-sort/__test__/BCISort.test.js

@@ -0,0 +1,55 @@
+import BCIS from '../BCIS';
+import {
+  equalArr,
+  notSortedArr,
+  reverseArr,
+  sortedArr,
+  SortTester,
+} from '../../SortTester';
+
+// Complexity constants.
+const SORTED_ARRAY_VISITING_COUNT = 0;
+const NOT_SORTED_ARRAY_VISITING_COUNT = 0;
+const REVERSE_SORTED_ARRAY_VISITING_COUNT = 0;
+const EQUAL_ARRAY_VISITING_COUNT = 0;
+
+describe('BCIS', () => {
+  it('should sort array', () => {
+    SortTester.testSort(BCIS);
+  });
+
+  it('should sort array with custom comparator', () => {
+    SortTester.testSortWithCustomComparator(BCIS);
+  });
+  it('should visit EQUAL array element specified number of times', () => {
+    SortTester.testAlgorithmTimeComplexity(
+      BCIS,
+      equalArr,
+      EQUAL_ARRAY_VISITING_COUNT,
+    );
+  });
+
+  it('should visit SORTED array element specified number of times', () => {
+    SortTester.testAlgorithmTimeComplexity(
+      BCIS,
+      sortedArr,
+      SORTED_ARRAY_VISITING_COUNT,
+    );
+  });
+
+  it('should visit NOT SORTED array element specified number of times', () => {
+    SortTester.testAlgorithmTimeComplexity(
+      BCIS,
+      notSortedArr,
+      NOT_SORTED_ARRAY_VISITING_COUNT,
+    );
+  });
+
+  it('should visit REVERSE SORTED array element specified number of times', () => {
+    SortTester.testAlgorithmTimeComplexity(
+      BCIS,
+      reverseArr,
+      REVERSE_SORTED_ARRAY_VISITING_COUNT,
+    );
+  });
+});