Implementing Quick Sort. Closes #2

lucasfcosta · Aug 23, 2015 · d09b00e · d09b00e
1 parent 2d83991
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diff --git a/lib/sorter.js b/lib/sorter.js
@@ -295,6 +295,103 @@ var Sorter = function(array) {
       return _elements;
     }
   };
+
+  function _partitionArray(left, right) {
+    var pivot = _elements[Math.floor((right + left) / 2)];
+    var i = left;
+    var j = right;
+
+    while (i <= j) {
+      while (_elements[i] < pivot) {
+        i++;
+      }
+
+      while (_elements[j] > pivot) {
+        j--;
+      }
+
+      if (i <= j) {
+        var tmp = _elements[i];
+        _elements[i] = _elements[j];
+        _elements[j] = tmp;
+        i++;
+        j--;
+      }
+    }
+
+    return i;
+  }
+
+  function _quickSortArray(left, right) {
+    var index;
+
+    if (_elements.length > 1) {
+      index = _partitionArray(left, right);
+
+      if (left < index - 1) {
+        _quickSortArray(left, index - 1);
+      }
+
+      if (index < right) {
+        _quickSortArray(index, right);
+      }
+    }
+
+    return _elements;
+  }
+
+  function _partition(left, right) {
+    var pivot = _elements[Math.floor((right + left) / 2)][1];
+    var i = left;
+    var j = right;
+
+    while (i <= j) {
+      while (_elements[i][1] < pivot) {
+        i++;
+      }
+
+      while (_elements[j][1] > pivot) {
+        j--;
+      }
+
+      if (i <= j) {
+        var tmp = _elements[i];
+        _elements[i] = _elements[j];
+        _elements[j] = tmp;
+        i++;
+        j--;
+      }
+    }
+
+    return i;
+  }
+
+  function _quickSort(left, right) {
+    var index;
+
+    if (_elements.length > 1) {
+      index = _partition(left, right);
+
+      if (left < index - 1) {
+        _quickSort(left, index - 1);
+      }
+
+      if (index < right) {
+        _quickSort(index, right);
+      }
+    }
+
+    return _elements;
+  }
+
+  this.quickSort = function() {
+    if (_simpleArray) {
+      return _quickSortArray(0, _elements.length - 1);
+    } else {
+      _elements = _clearObjectArray(_quickSort(0, _elements.length - 1));
+      return _elements;
+    }
+  };
 
 };
 

diff --git a/test/sorting.js b/test/sorting.js
@@ -259,3 +259,48 @@ describe('Heap Sort', function () {
     assert.equal(sorter.getElements()[2], objectArray[0]);
   });
 });
+
+describe('Quick Sort', function () {
+  it('Should sort the simple array correctly', function () {
+    var sorter = new Sorter(aSimpleArray);
+
+    assert.equal(sorter.quickSort().length, 6);
+
+    for (var i = 0; i < sorter.getElements().length; i++) {
+      assert.equal(sorter.getElements()[i], aSimpleArraySorted[i]);
+    }
+  });
+
+  it('Should sort the object array by the selected property path', function () {
+    var sorter = new Sorter(objectArray);
+
+    assert.equal(sorter.sortBy('.age').quickSort().length, 3);
+    assert.equal(sorter.getElements()[0], objectArray[1]);
+    assert.equal(sorter.getElements()[1], objectArray[0]);
+    assert.equal(sorter.getElements()[2], objectArray[2]);
+
+    assert.equal(sorter.sortBy('.userId').quickSort().length, 3);
+    assert.equal(sorter.getElements()[0], objectArray[2]);
+    assert.equal(sorter.getElements()[1], objectArray[0]);
+    assert.equal(sorter.getElements()[2], objectArray[1]);
+
+    assert.equal(sorter.sortBy('.height').quickSort().length, 3);
+    assert.equal(sorter.getElements()[0], objectArray[0]);
+    assert.equal(sorter.getElements()[1], objectArray[2]);
+    assert.equal(sorter.getElements()[2], objectArray[1]);
+
+    assert.equal(sorter.sortBy('.yearsUntilGraduation').quickSort().length, 3);
+    assert.equal(sorter.getElements()[0], objectArray[2]);
+    assert.equal(sorter.getElements()[1], objectArray[0]);
+    assert.equal(sorter.getElements()[2], objectArray[1]);
+  });
+
+  it('Should sort nested properties', function () {
+    var sorter = new Sorter(objectArray);
+
+    assert.equal(sorter.sortBy('.family.numberOfChildren').quickSort().length, 3);
+    assert.equal(sorter.getElements()[0], objectArray[1]);
+    assert.equal(sorter.getElements()[1], objectArray[2]);
+    assert.equal(sorter.getElements()[2], objectArray[0]);
+  });
+});