Merge 072377e into 9716d2f

algorithms/sorting/shell_sort.js

@@ -0,0 +1,29 @@
+'use strict';
+var Comparator = require('../../util/comparator');
+/**
+ * shell sort  worst:O(n lg n)  best:O(n)
+ */
+var shellSort = function (array, comparatorFn) {
+	var comparator = new Comparator(comparatorFn),
+		begin = 0,
+		end = array.length - 1,
+		gap = parseInt((end - begin + 1) / 2),
+		i = 0, j = 0, temp = 0;
+
+	while (gap >= 1) {
+		for (i = begin + gap;i <= end;i += 1) {
+			temp = array[i];
+			j = i - gap;
+			while (j >= begin && comparator.greaterThan(array[j], temp)) {
+				array[j + gap] = array[j];
+				j = j - gap;
+			}
+			array[j + gap] = temp;
+		}
+		gap = parseInt(gap / 2);
+	}
+
+	return array;
+};
+
+module.exports = shellSort;

test/algorithms/sorting/shell_sort.js

@@ -0,0 +1,42 @@
+'use strict';
+
+var shellSort = require('../../../algorithms/sorting/shell_sort'),
+	assert = require('assert');
+
+describe('shellSort', function () {
+	it('should sort the given array', function () {
+		assert.deepEqual(shellSort([]), []);
+		assert.deepEqual(shellSort([1]), [1]);
+		assert.deepEqual(shellSort([2, 1]), [1, 2]);
+		assert.deepEqual(shellSort([3, 1, 2]), [1, 2, 3]);
+		assert.deepEqual(shellSort([1, 2, 3, 4, 5, 6]), [1, 2, 3, 4, 5, 6]);
+		assert.deepEqual(shellSort([6, 5, 4, 3, 2, 1]), [1, 2, 3, 4, 5, 6]);
+		assert.deepEqual(shellSort([1, 295, 3, 6, 8, 10, 10, 20, 0, 5]),
+			[0, 1, 3, 5, 6, 8, 10, 10, 20, 295]);
+	});
+
+	it('should sort the array with a specific comparison function', function () {
+		var compare = function (a, b) {
+			if (a.length === b.length) return 0;
+			return a.length < b.length ? -1 : 1;
+		};
+		assert.deepEqual(shellSort([], compare), []);
+		assert.deepEqual(shellSort(['apple'], compare), ['apple']);
+		assert.deepEqual(shellSort(['apple', 'banana'], compare),
+			['apple', 'banana']);
+		assert.deepEqual(shellSort(['apple', 'banana', 'car'], compare),
+			['car', 'apple', 'banana']);
+		assert.deepEqual(shellSort(['apple', 'banana', 'car', 'z'], compare),
+			['z', 'car', 'apple', 'banana']);
+
+		var reverseSort = function (a, b) {
+			if (a == b) return 0;
+			return a < b ? 1 : -1;
+		};
+		assert.deepEqual(shellSort([1, 295, 3, 6, 8, 10, 10, 20, 0, 5],
+			reverseSort),
+			[295, 20, 10, 10, 8, 6, 5, 3, 1, 0]);
+	});
+});
+
+