Shellsort added

mgechev · mgechev · commit bfffaaf511b6 · 2013-02-12T22:24:28.000+02:00
diff --git a/src/sorting/shellsort.js b/src/sorting/shellsort.js
@@ -0,0 +1,34 @@
+/**
+ * Shellsort
+ *
+ * Shellsort uses the gaps 701, 301, 132, 57, 23, 10, 4, 1 and uses insertion sort
+ * to sort the sub-arrays which match for the different gaps.
+ */
+var shellsort = (function () {
+
+    var gaps = [701, 301, 132, 57, 23, 10, 4, 1];
+
+    /**
+     * Shellsort which uses the gaps in the lexical scope of the IIFE.
+     *
+     * @public
+     * @param {array} array Array which should be sorted
+     * @return {array} Sorted array
+     */
+    return function (array) {
+        var gap, current;
+
+        for (var k = 0; k < gaps.length; k += 1) {
+            gap = gaps[k];
+            for (var i = gap; i < array.length; i += gap) {
+                current = array[i];
+                for (var j = i; j >= gap && array[j - gap] > current; j -= gap) {
+                    array[j] = array[j - gap];
+                }
+                array[j] = current;
+            }
+        }
+        return array;
+    };
+
+}());
