using System;
using System.Collections.Generic;

public class Test
{
    static void Main()
    {
        int[] ints = { 10001, 10002, 10003, 10004, 10005 };
        int hash = GetHashCode(ints);
        int[] reorderedInts = { 10004, 10002, 10005, 10001, 10003 };
        int reorderedHash = GetHashCode(reorderedInts);

        Console.WriteLine("hash          == {0}", hash);
        Console.WriteLine("hashReordered == {0}", reorderedHash);
    }

    static int GetHashCode(IEnumerable<int> integers)
    {
        int hash = 0;

        foreach(int integer in integers)
        {
            int x = integer;

            x ^= x >> 17;
            x *= 830770091;   // 0xed5ad4bb
            x ^= x >> 11;
            x *= -1404298415; // 0xac4c1b51
            x ^= x >> 15;
            x *= 830770091;   // 0x31848bab
            x ^= x >> 14;

            hash += x;
        }

        return hash;
    }
}