c# – 所有匹配的Boyer-Moore-Horspool算法(在字节数组中查找字
发布时间:2020-12-15 08:39:14 所属栏目:百科 来源:网络整理
导读:这是我对BMH算法的实现(它就像一个魅力): public static Int64 IndexOf(this Byte[] value,Byte[] pattern){ if (value == null) throw new ArgumentNullException("value"); if (pattern == null) throw new ArgumentNullException("pattern"); Int64 valu
这是我对BMH算法的实现(它就像一个魅力):
public static Int64 IndexOf(this Byte[] value,Byte[] pattern) { if (value == null) throw new ArgumentNullException("value"); if (pattern == null) throw new ArgumentNullException("pattern"); Int64 valueLength = value.LongLength; Int64 patternLength = pattern.LongLength; if ((valueLength == 0) || (patternLength == 0) || (patternLength > valueLength)) return -1; Int64[] badCharacters = new Int64[256]; for (Int64 i = 0; i < 256; ++i) badCharacters[i] = patternLength; Int64 lastPatternByte = patternLength - 1; for (Int64 i = 0; i < lastPatternByte; ++i) badCharacters[pattern[i]] = lastPatternByte - i; // Beginning Int64 index = 0; while (index <= (valueLength - patternLength)) { for (Int64 i = lastPatternByte; value[(index + i)] == pattern[i]; --i) { if (i == 0) return index; } index += badCharacters[value[(index + lastPatternByte)]]; } return -1; } 我试图修改它以返回所有匹配而不是仅返回第一个索引,但我到处都得到IndexOutOfRangeException D: 显然我错过了一些重要的东西,或者我没有正确理解它是如何工作的.我究竟做错了什么? public static List<Int64> IndexesOf(this Byte[] value,Byte[] pattern) { if (value == null) throw new ArgumentNullException("value"); if (pattern == null) throw new ArgumentNullException("pattern"); Int64 valueLength = value.LongLength; Int64 patternLength = pattern.LongLength; if ((valueLength == 0) || (patternLength == 0) || (patternLength > valueLength)) return (new List<Int64>()); Int64[] badCharacters = new Int64[256]; for (Int64 i = 0; i < 256; ++i) badCharacters[i] = patternLength; Int64 lastPatternByte = patternLength - 1; for (Int64 i = 0; i < lastPatternByte; ++i) badCharacters[pattern[i]] = lastPatternByte - i; // Beginning Int64 index = 0; List<Int64> indexes = new List<Int64>(); while (index <= (valueLength - patternLength)) { for (Int64 i = lastPatternByte; value[(index + i)] == pattern[i]; --i) { if (i == 0) indexes.Add(index); } index += badCharacters[value[(index + lastPatternByte)]]; } return indexes; } 解决方法
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if (i == 0) indexes.Add(index); 至 if (i == 0) { indexes.Add(index); break; } (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |