fork download
copy 
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4.  
  5. public class Test
  6. {
  7.     private static IEnumerable<T> Swap<T>(IEnumerable<T> source, int smallerIndex, int greaterIndex) {
  8. using (IEnumerator<T> e = source.GetEnumerator()) {
  9.     IList<T> saved = new List<T>(greaterIndex-smallerIndex+1);
  10.     int index = 0;
  11.     while (e.MoveNext()) {
  12.         // If we're outside the swapped indexes, yield return the current element
  13.         if (index < smallerIndex || index > greaterIndex) {
  14.             index++;
  15.             yield return e.Current;
  16.         } else if (index == smallerIndex) {
  17.             var atSmaller = e.Current;
  18.             // Save all elements starting with the current one into a list;
  19.             // Continue until you find the last index, or exhaust the sequence.
  20.             while (index != greaterIndex && e.MoveNext()) {
  21.                 saved.Add(e.Current);
  22.                 index++;
  23.             }
  24.             // Make sure we're here because we got to the greaterIndex,
  25.             // not because we've exhausted the sequence
  26.             if (index == greaterIndex) {
  27.                 // If we are OK, return the element at greaterIndex
  28.                 yield return e.Current;
  29.             }
  30.             // Enumerate the saved items
  31.             for (int i = 0 ; i < saved.Count-1 ; i++) {
  32.                 yield return saved[i];
  33.             }
  34.             // Finally, return the item at the smallerIndex
  35.             yield return atSmaller;
  36.             index++;
  37.         }
  38.     }
  39. }
  40.     }
  41. 	public static void Main()
  42. 	{
  43.         var data = new[] {0,1,2,3,4,5,6};
  44.         foreach (var x in Swap(data, 2, 5)) {
  45.             Console.WriteLine(x);
  46.         }
  47.  
  48. 	}
  49. }
Success #stdin #stdout 0.03s 33984KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
0
1
5
3
4
2
6
https://ideone.com/YSh9im
language:
C# (gmcs 5.20.1)
created:
10 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!