using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var arr = new List<int> { 1, 3, 5, 2, 4, 8, 7, 10 };

        var inspectedElements = 0;

        var currentElementIndex = arr.Count-1;

        while (inspectedElements < arr.Count)

        {

            inspectedElements++;

            var el = arr[currentElementIndex];

            if (el % 2 == 1)

            {

                currentElementIndex--;

                continue;

            }

            arr.Remove(el);

            arr.Insert(0, el);

        }

        foreach (var item in arr)

        {

            Console.Write(item + " ");

        }

    }

}

​

// 1 3 5 2 4 8 7 10

// output: 2 4 8 10 1 3 5 7