Just another update

Task/Dutch-national-flag-problem/Java/dutch-national-flag-problem.java

@@ -0,0 +1,46 @@
+import java.util.Arrays;
+import java.util.Random;
+
+public class DutchNationalFlag {
+    enum DutchColors {
+        RED, WHITE, BLUE
+    }
+
+    public static void main(String[] args) {
+        DutchColors[] balls = new DutchColors[12];
+
+        DutchColors[] values = DutchColors.values();
+        Random rand = new Random();
+        for (int i = 0; i < balls.length; i++)
+            balls[i] = values[rand.nextInt(values.length)];
+
+        System.out.println("Before: " + Arrays.toString(balls));
+
+        dutchNationalFlagSort(balls);
+
+        System.out.println("After : " + Arrays.toString(balls));
+    }
+
+    private static void dutchNationalFlagSort(DutchColors[] items) {
+        int lo = 0, mid = 0, hi = items.length - 1;
+
+        while (mid <= hi)
+            switch (items[mid]) {
+                case RED:
+                    swap(items, lo++, mid++);
+                    break;
+                case WHITE:
+                    mid++;
+                    break;
+                case BLUE:
+                    swap(items, mid, hi--);
+                    break;
+            }
+    }
+
+    private static void swap(DutchColors[] arr, int a, int b) {
+        DutchColors tmp = arr[a];
+        arr[a] = arr[b];
+        arr[b] = tmp;
+    }
+}