/// <summary>
/// https://adventofcode.com/2020/day/9#part2
/// </summary>
public static void Part2()
{
var cypher = new XmasCypher(Input.GetLines(9).Select(BigInteger.Parse));
var key = cypher.FindKey(cypher.FindNonSumNumber()).ToArray();
Console.WriteLine(key.Min() + key.Max());
}
/// <summary>
/// https://adventofcode.com/2020/day/9
/// </summary>
public static void Part1()
{
var cypher = new XmasCypher(Input.GetLines(9).Select(BigInteger.Parse));
var nonSumNumber = cypher.FindNonSumNumber();
Console.WriteLine(nonSumNumber);
}