tasks a-s

Task/Range-extraction/C-sharp/range-extraction.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+class RangeExtraction
+{
+    static void Main()
+    {
+        const string testString = "0,  1,  2,  4,  6,  7,  8, 11, 12, 14,15, 16, 17, 18, 19, 20, 21, 22, 23, 24,25, 27, 28, 29, 30, 31, 32, 33, 35, 36,37, 38, 39";
+        var result = String.Join(",", RangesToStrings(GetRanges(testString)));
+        Console.Out.WriteLine(result);
+    }
+
+    public static IEnumerable<IEnumerable<int>> GetRanges(string testString)
+    {
+        var numbers = testString.Split(new[] { ',' }).Select(x => Convert.ToInt32(x));
+        var current = new List<int>();
+        foreach (var n in numbers)
+        {
+            if (current.Count == 0)
+            {
+                current.Add(n);
+            }
+            else
+            {
+                if (current.Max() + 1 == n)
+                {
+                    current.Add(n);
+                }
+                else
+                {
+                    yield return current;
+                    current = new List<int> { n };
+                }
+            }
+        }
+        yield return current;
+    }
+
+    public static IEnumerable<string> RangesToStrings(IEnumerable<IEnumerable<int>> ranges)
+    {
+        foreach (var range in ranges)
+        {
+            if (range.Count() == 1)
+            {
+                yield return range.Single().ToString();
+            }
+            else if (range.Count() == 2)
+            {
+                yield return range.Min() + "," + range.Max();
+            }
+            else
+            {
+                yield return range.Min() + "-" + range.Max();
+            }
+        }
+    }
+}