这是我对BMH算法的实现(它就像一种魅力):
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;
}
我试图对其进行修改,以便返回所有匹配项而不是仅返回第一个索引,但是我到处都是D:
显然,我缺少重要的东西,或者我没有正确理解它的工作原理。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;
}
最佳答案
改变
if (i == 0)
indexes.Add(index);
至
if (i == 0)
{
indexes.Add(index);
break;
}
关于c# - 所有匹配项的Boyer-Moore-Horspool算法(在Byte数组内部查找Byte数组),我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/16252518/