alexandrnikitin / ahocorasick.net Goto Github PK

Consider this input:

var sut = new AhoCorasickTree(new[] { "abcd", "bc" });
var x = sut.Contains("abc"); // => false

This should yield true because "abc" contains "bc". The failure transition from "c" of the "abcd" subtree to the "c" of "bc" seems to be missing.

Using the following code:

List<string> uniqueWords = new();
static string? parsedTermsComplete;

public void AttemptOne()
{
    var wordArray = uniqueWords.ToArray();
    var keyWords = new AhoCorasickTree(wordArray);
    var keywordsPositions = keyWords.Search(parsedTermsComplete).ToList();
    // var result = keyWords.Contains(parsedTermsComplete!); - alternative still fails.
}

I get the following error:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
---> System.ArgumentException: should contain keywords
at AhoCorasick.Net.AhoCorasickTree..ctor(String[] keywords)
at RegexTesting.Program.Attempts.AttemptOne() in C:\Demo\RegexTesting\RegexTesting\Program.cs:line 1058
at BenchmarkDotNet.Autogenerated.Runnable_0.WorkloadActionNoUnroll(Int64 invokeCount) in C:\Demo\RegexTesting\RegexTesting\bin\Release\net6.0\b224fdac-806c-4a65-a8ce-8efc0ea02b10\b224fdac-806c-4a65-a8ce-8efc0ea02b10.notcs:line 318
at BenchmarkDotNet.Engines.Engine.RunIteration(IterationData data)
at BenchmarkDotNet.Engines.EngineFactory.Jit(Engine engine, Int32 jitIndex, Int32 invokeCount, Int32 unrollFactor)
at BenchmarkDotNet.Engines.EngineFactory.CreateReadyToRun(EngineParameters engineParameters)
at BenchmarkDotNet.Autogenerated.Runnable_0.Run(IHost host, String benchmarkName) in C:\Demo\RegexTesting\RegexTesting\bin\Release\net6.0\b224fdac-806c-4a65-a8ce-8efc0ea02b10\b224fdac-806c-4a65-a8ce-8efc0ea02b10.notcs:line 175
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle.InvokeMethod(Object target, Span`1& arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
at BenchmarkDotNet.Autogenerated.UniqueProgramName.AfterAssemblyLoadingAttached(String[] args) in C:\Demo\RegexTesting\RegexTesting\bin\Release\net6.0\b224fdac-806c-4a65-a8ce-8efc0ea02b10\b224fdac-806c-4a65-a8ce-8efc0ea02b10.notcs:line 58

The following code works in the same benchmark suite - so it isn't that the list is empty....

public void AttemptTwo()
{
    var wordArray = uniqueWords.ToArray();
    int i = uniqueWords.Count - 1;
    foreach (var item in wordArray)
    {
        var keyWords = new AhoCorasickTree(new[] { item });
        if (keyWords.Contains(parsedTermsComplete))
        {
            uniqueWords.RemoveAt(i);
        }
        i--;
    }
}

Not sure if I have misunderstood the implementation, but wanted to raise it as I thought that this would work.

For implementation, parsedTermsComplete should contain several copies of every single word in the uniqueWords List - as that is how the parsed terms were created - I was looking to find a way to QC that every single word in uniqueWords did in fact exist in the parsedTermsComplete.

Don't get me wrong, the implementation that works is super fast, 3 times faster than any other implementation of the test - just wondered why I can't use a List to Array.

Something like this:

public IEnumerable<KeyValuePair<string, int>> Search(string text)
{ ... }

where the key is the matched pattern and the value is the start index into the searched string.

I tried adding this method assuming that IsFinished means a node is in the dictionary ("blue node" as in the description on Wikipedia). But that doesn't seem to be the case so I gave up 😢