AdamWhiteHat

/// <summary>
/// A generic Vector class.
/// Uses/Requires the GenericArithmeticFactory class:
/// https://gist.github.com/AdamWhiteHat/71d548ebfb2ee67fcbd78a39a9751423
/// </summary>
public class Vector<T>
{
	/// <summary>The dimension of the vector, i.e. the number of elements or its length.</summary>
	public int Dimensions { get { return Elements == null ? 0 : Elements.Length; } }

AdamWhiteHat

/// <summary>Abelian Sandpile Class</summary>
public class SandPile : IEquatable<SandPile>
{
	#region static Sandpile Values

	public static SandPile Zero = new SandPile(new int[,] { { 2, 1, 2 }, { 1, 0, 1 }, { 2, 1, 2 } }, 4);
	public static SandPile One = new SandPile(new int[,] { { 3, 2, 3 }, { 2, 1, 2 }, { 3, 2, 3 } }, 4);
	public static SandPile NegativeOne = new SandPile(new int[,] { { 1, 3, 1 }, { 3, 3, 3 }, { 1, 3, 1 } }, 4);

	// These can all be constructed from the above three sandpiles.

AdamWhiteHat

/// <summary>
/// A IEqualityComparer<string> that provides the mathematically best GetHashCode
/// possible for adding millions of strings to Dictionaries, HashTables, HashMaps and more.
/// It works by interpreting an array of bytes (your string) as a number in base 256,
/// and then returning the unit of that number in the multiplicative group of integers modulo a prime p,
/// where p is the largest prime less than 2^32.
/// </summary>
public class BestStringEqualityComparer : IEqualityComparer<string>
{
	public int GetHashCode(string obj)

AdamWhiteHat

namespace ComponentModelEx
{
    public delegate void PropertyChangedExEventHandler(object sender, PropertyChangedExEventArgs e);

    public interface INotifyPropertyChangedEx
    {
        event PropertyChangedExEventHandler PropertyChangedEx;
    }
}

AdamWhiteHat

using System;
using System.Collections.Generic;

namespace ComponentModelEx
{
	public class DictionaryChangedEventArgs<TKey, TValue> : EventArgs
	{
		public DictionaryChangedAction Action => _action;
		public KeyValuePair<TKey, TValue> OldValue => _oldValue;
		public KeyValuePair<TKey, TValue> NewValue => _newValue;

AdamWhiteHat

public static bool IPv6Check(string input)
{
    if (string.IsNullOrWhiteSpace(input))
    {
        return false;
    }

    if (input.IndexOf("::") != input.LastIndexOf("::")) // 'The "::" can only appear once in an address.'
    {
        return false;

AdamWhiteHat

public static class GenericArithmeticFactory<T>
{
    private static Dictionary<ExpressionType, Func<T, T, T>> _binaryOperationDictionary;
    private static Dictionary<ExpressionType, Func<T, T, bool>> _comparisonOperationDictionary;
    private static Func<T, T> _sqrtOperation = null;

    static GenericArithmeticFactory()
    {
        _binaryOperationDictionary = new Dictionary<ExpressionType, Func<T, T, T>>();
        _comparisonOperationDictionary = new Dictionary<ExpressionType, Func<T, T, bool>>();

AdamWhiteHat

/// <summary>
/// Requires the BCrypt nuget package. Available here: https://www.nuget.org/packages/BCrypt.Net-Next
/// </summary>
public static class PasswordHashing
{
	public static string HashPassword(string password, int workFactor)
	{
		return BCrypt.Net.BCrypt.HashPassword(password, workFactor);
	}

AdamWhiteHat

public static class FastFactorial
{
	public static BigInteger Factorial(BigInteger n)
	{
		return MultiplyRange(2, n);
	}

	private static BigInteger MultiplyRange(BigInteger from, BigInteger to)
	{
		var diff = to - from;

AdamWhiteHat

using System;
using System.Linq;
using System.Numerics;
using System.Collections.Generic;

public static class Maths
{
	/// <summary>
	/// Legendre Symbol returns 1 for a (nonzero) quadratic residue mod p, -1 for a non-quadratic residue (non-residue), or 0 on zero.
	/// </summary>