aoc2021/aoc2021/Extensions.cs

77 lines
2.4 KiB
C#

using System.Numerics;
namespace aoc2021;
public static class Extensions
{
/// <summary>
/// increased accuracy for stopwatch based on frequency.
/// <see
/// href="http://geekswithblogs.net/BlackRabbitCoder/archive/2012/01/12/c.net-little-pitfalls-stopwatch-ticks-are-not-timespan-ticks.aspx">
/// blog
/// details here
/// </see>
/// </summary>
/// <param name="stopwatch"></param>
/// <returns></returns>
public static double ScaleMilliseconds(this Stopwatch stopwatch) =>
1_000 * stopwatch.ElapsedTicks / (double)Stopwatch.Frequency;
/// <summary>
/// Does a <see cref="Range"/> include a given int?
/// </summary>
/// <param name="range"></param>
/// <param name="i"></param>
/// <returns></returns>
public static bool Contains(this Range range, int i) =>
i >= range.Start.Value && i <= range.End.Value;
/// <summary>
/// Creates a new BigInteger from a binary (Base2) string
/// <see href="https://gist.github.com/mjs3339/73042bc0e717f98796ee9fa131e458d4" />
/// </summary>
public static BigInteger BigIntegerFromBinaryString(this string binaryValue)
{
BigInteger res = 0;
if (binaryValue.Count(b => b == '1') + binaryValue.Count(b => b == '0') != binaryValue.Length) return res;
foreach (var c in binaryValue)
{
res <<= 1;
res += c == '1' ? 1 : 0;
}
return res;
}
public static IEnumerable<IEnumerable<T>> Permute<T>(this IEnumerable<T> list)
{
var array = list as T[] ?? list.ToArray();
return array.Length == 1
? new[] { array }
: array.SelectMany(t => Permute(array.Where(x => !x!.Equals(t))), (v, p) => p.Prepend(v));
}
public static int Pow(this int i, int power)
{
var pow = (uint) power;
var ret = 1;
while (pow != 0)
{
if ((pow & 1) == 1) ret *= i;
i *= i;
pow >>= 1;
}
return ret;
}
public static IEnumerable<KeyValuePair<int, T>> Indexed<T>(this IEnumerable<T> source)
{
return source.Select((t, i) => new KeyValuePair<int, T>(i, t));
}
public static IEnumerable<KeyValuePair<TKey, TValue>> WhereValue<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> source, Func<TValue, bool> func)
{
return source.Where(pair => func(pair.Value));
}
}