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C# Radix
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| public static class ListExtensions | |
| { | |
| public static void RadixSort<T>(this List<T> list, Func<T, uint> orderBy) | |
| { | |
| RadixCountBytesSort(list, orderBy); | |
| } | |
| private static void RadixCountBytesSort<T>(List<T> list, Func<T, uint> orderOf) | |
| { | |
| var count = list.Count; | |
| var keys = ArrayPool<uint>.Shared.Rent(count); | |
| var buffer = ArrayPool<T>.Shared.Rent(count); | |
| for (var i = 0; i < count; i++) | |
| keys[i] = orderOf(list[i]); | |
| for (var shift = 0; shift < 32; shift += 8) | |
| { | |
| CountSort8Bits(list, buffer, keys, shift); | |
| } | |
| ArrayPool<uint>.Shared.Return(keys); | |
| ArrayPool<T>.Shared.Return(buffer, clearArray: true); | |
| } | |
| private static void CountSort8Bits<T>(List<T> input, T[] buffer, uint[] keys, int shift) | |
| { | |
| var count = input.Count; | |
| var buckets = ArrayPool<int>.Shared.Rent(256); | |
| for (var i = 0; i < count; i++) | |
| buckets[(keys[i] >> shift) & 0xFF]++; | |
| for (var i = 1; i < 256; i++) | |
| buckets[i] += buckets[i - 1]; | |
| for (var i = count - 1; i >= 0; i--) | |
| { | |
| var bucket = (keys[i] >> shift) & 0xFF; | |
| var pos = --buckets[bucket]; | |
| buffer[pos] = input[i]; | |
| } | |
| for (var i = 0; i < count; i++) | |
| input[i] = buffer[i]; | |
| ArrayPool<int>.Shared.Return(buckets); | |
| } | |
| } |
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