wiggle sort easy way: done

Author: rampatra

src/me/ramswaroop/arrays/sorting/WiggleSort.java

@@ -0,0 +1,45 @@
+package me.ramswaroop.arrays.sorting;
+
+import java.util.Arrays;
+
+/**
+ * Wiggle Sort: Arrange the elements in the array such that elements in
+ * even indices are greater than or equal to its neighbouring elements
+ * and elements in odd indices are less than or equal to its neighbouring
+ * elements. In other words, all elements in array {@code a} are arranged
+ * such that, a[i-1] <= a[i] => a[i+1]
+ * <p>
+ * Ex: {1, 3, 2, 5, 4, 6}
+ *
+ * @author ramswaroop
+ * @version 01/09/2016
+ */
+public class WiggleSort {
+
+    public static int[] wiggleSortEasyWay(int[] a) {
+        a = MergeSort.mergeSort(a);
+        for (int i = 1; i < a.length; i += 2) {
+            swap(a, i, i + 1);
+        }
+        return a;
+    }
+
+    private static void swap(int[] a, int index1, int index2) {
+        if (index2 >= a.length) return;
+
+        a[index1] = a[index1] + a[index2];
+        a[index2] = a[index1] - a[index2];
+        a[index1] = a[index1] - a[index2];
+    }
+
+    public static void main(String[] a) {
+        int[] ar = {3, 5, 6, 7, 8, 1, 2};
+        System.out.println(Arrays.toString(wiggleSortEasyWay(ar)));
+        int[] ar1 = {3, 5, 6, 7, 2, 1};
+        System.out.println(Arrays.toString(wiggleSortEasyWay(ar1)));
+        int[] ar2 = {3, 5, 6, 7, 8, 1};
+        System.out.println(Arrays.toString(wiggleSortEasyWay(ar2)));
+        int[] ar3 = {3, 5, 6, 5, 8, 1};
+        System.out.println(Arrays.toString(wiggleSortEasyWay(ar3)));
+    }
+}