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