using System;
using System.Linq;
 
using System.Collections.Generic;
 
namespace Yoba{
 
public class Test
{
	public static void Main()
	{
		var source = new int[] {1, 2, 3, 4, 5, 6, 7};
 
		Action<int[]> output = (t) => Console.WriteLine(t.Aggregate(string.Empty, (s, s1)=>string.Format("{0}, {1}", s, s1)).Trim(new char[]{',',' '}));
 
		output(source);
		source = Enumerable.Range(0, source.Length).Select(x => source[Math.Min(x + 1 - x % 2 * 2, source.Length - 1)]).ToArray();
		output(source);
 
	}
}
}

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