public static void Main()
Console.WriteLine("Hello World");
Console.WriteLine("{0}", string.Join(", ", DutchNationalProblem(new int[] {1, 0, 2, 1, 0} )));
public static int[] DutchNationalProblem ( int[] arr) {
int right =arr.GetLength(0)-1;
for (int i=0;i<arr.GetLength(0); i++)
Console.WriteLine(" {0} {1} : {2}", left, right, string.Join(", ", arr));
public static void swap(int left, int right, int[] arr) {