Data commit

Task/Dutch-national-flag-problem/C-sharp/dutch-national-flag-problem.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace RosettaCode
+{
+    class Program
+    {
+        static void QuickSort(IComparable[] elements, int left, int right)
+        {
+            int i = left, j = right;
+            IComparable pivot = elements[left + (right - left) / 2];
+
+            while (i <= j)
+            {
+                while (elements[i].CompareTo(pivot) < 0) i++;
+                while (elements[j].CompareTo(pivot) > 0) j--;
+
+                if (i <= j)
+                {
+                    // Swap
+                    IComparable tmp = elements[i];
+                    elements[i] = elements[j];
+                    elements[j] = tmp;
+                    i++;
+                    j--;
+                }
+            }
+
+            // Recursive calls
+            if (left < j) QuickSort(elements, left, j);
+            if (i < right) QuickSort(elements, i, right);
+        }
+        const int NUMBALLS = 5;
+        static void Main(string[] args)
+        {
+            Func<string[], bool> IsSorted = (ballList) =>
+                {
+                    int state = 0;
+                    for (int i = 0; i < NUMBALLS; i++)
+                    {
+                        if (int.Parse(ballList[i]) < state)
+                            return false;
+                        if (int.Parse(ballList[i]) > state)
+                            state = int.Parse(ballList[i]);
+                    }
+                    return true;
+                };
+            Func<string[], string> PrintOut = (ballList2) =>
+                {
+                    StringBuilder str = new StringBuilder();
+                    for (int i = 0; i < NUMBALLS; i++)
+                        str.Append(int.Parse(ballList2[i]) == 0 ? "r" : int.Parse(ballList2[i]) == 1 ? "w" : "b");
+                    return str.ToString();
+                };
+            bool continueLoop = true;
+            string[] balls = new string[NUMBALLS]; // 0 = r, 1 = w, 2 = b
+            Random numberGenerator = new Random();
+            do // Enforce that we start with non-sorted balls
+            {
+                // Generate balls
+                for (int i = 0; i < NUMBALLS; i++)
+                    balls[i] = numberGenerator.Next(3).ToString();
+
+                continueLoop = IsSorted(balls);
+                if (continueLoop)
+                    Console.WriteLine("Accidentally still sorted: {0}", PrintOut(balls));
+            } while (continueLoop);
+            Console.WriteLine("Non-sorted: {0}", PrintOut(balls));
+            QuickSort(balls, 0, NUMBALLS - 1); // Sort them using quicksort
+            Console.WriteLine("{0}: {1}", IsSorted(balls) ? "Sorted" : "Sort failed", PrintOut(balls));
+        }
+    }
+}