Data commit

Task/Stream-merge/C-sharp/stream-merge.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace RosettaCode
+{
+    static class StreamMerge
+    {
+        static IEnumerable<T> Merge2<T>(IEnumerable<T> source1, IEnumerable<T> source2) where T : IComparable
+        {
+            var q1 = new Queue<T>(source1);
+            var q2 = new Queue<T>(source2);
+            while (q1.Any() && q2.Any())
+            {
+                var c = q1.Peek().CompareTo(q2.Peek());
+                if (c <= 0) yield return q1.Dequeue(); else yield return q2.Dequeue();
+            }
+            while (q1.Any()) yield return q1.Dequeue();
+            while (q2.Any()) yield return q2.Dequeue();
+        }
+
+        static IEnumerable<T> MergeN<T>(params IEnumerable<T>[] sources) where T : IComparable
+        {
+            var queues = sources.Select(e => new Queue<T>(e)).Where(q => q.Any()).ToList();
+            var headComparer = Comparer<Queue<T>>.Create((x, y) => x.Peek().CompareTo(y.Peek()));
+            queues.Sort(headComparer);
+
+            while (queues.Any())
+            {
+                var q = queues.First();
+                queues.RemoveAt(0);
+                yield return q.Dequeue();
+                if (q.Any())
+                {
+                    var index = queues.BinarySearch(q, headComparer);
+                    queues.Insert(index < 0 ? ~index : index, q);
+                }
+            }
+        }
+
+        static void Main()
+        {
+            var a = new[] { 1, 4, 7, 10 };
+            var b = new[] { 2, 5, 8, 11 };
+            var c = new[] { 3, 6, 9, 12 };
+
+            foreach (var i in Merge2(a, b)) Console.Write($"{i} ");
+            Console.WriteLine();
+
+            foreach (var i in MergeN(a, b, c)) Console.Write($"{i} ");
+            Console.WriteLine();
+        }
+    }
+}