coded + unit tested

Author: Ram swaroop

src/me/ramswaroop/arrays/SymmetricDifference.java

@@ -0,0 +1,60 @@
+package me.ramswaroop.arrays;
+
+import java.util.Arrays;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 10/20/15
+ * @time: 11:34 PM
+ */
+public class SymmetricDifference {
+
+    /**
+     * Returns the symmetric difference between array {@param a1}
+     * and array {@param a2}.
+     * <p/>
+     * SYMMETRIC DIFFERENCE refers to the numbers which are present in
+     * only one of the arrays and not both.
+     *
+     * @param a1
+     * @param a2
+     * @return
+     */
+    public static int[] getSymmetricDifference(int[] a1, int[] a2) {
+        int index = 0;
+        int[] res = new int[a1.length + a2.length];
+
+        Arrays.sort(a1);
+        Arrays.sort(a2);
+
+        for (int i = 0, j = 0; i < a1.length || j < a2.length; ) {
+            if (j >= a2.length) {
+                res[index++] = a1[i];
+                i++;
+            } else if (i >= a1.length) {
+                res[index++] = a2[j];
+                j++;
+            } else if (a1[i] < a2[j]) {
+                res[index++] = a1[i];
+                i++;
+            } else if (a2[j] < a1[i]) {
+                res[index++] = a2[j];
+                j++;
+            } else {
+                i++;
+                j++;
+            }
+        }
+
+        return Arrays.copyOf(res, index);
+    }
+
+    public static void main(String a[]) {
+        System.out.println(Arrays.toString(getSymmetricDifference(new int[]{1, 2, 3, 4}, new int[]{2, 4, 5})));
+        System.out.println(Arrays.toString(getSymmetricDifference(new int[]{1, 2, 3, 4}, new int[]{5, 6, 7})));
+        System.out.println(Arrays.toString(getSymmetricDifference(new int[]{1, 2, 3, 4}, new int[]{5, 6, 7, 8})));
+        System.out.println(Arrays.toString(getSymmetricDifference(new int[]{1, 2, 3, 4}, new int[]{1, 2, 3, 4})));
+    }
+}