Question

I have a string like this:

inputString = "this is the first sentence in this book the first sentence is really the most interesting the first sentence is always first"

and a dictionary like this:

{   
   'always first': 0,
    'book the': 0,
    'first': 0,
    'first sentence': 0,
    'in this': 0,
    'interesting the': 0,
    'is always': 0,
    'is really': 0,
    'is the': 0,
    'most interesting': 0,
    'really the': 0,
    'sentence in': 0,
    'sentence is': 0,
    'the first': 0,
    'the first sentence': 0,
    'the first sentence is': 0,
    'the most': 0,
    'this': 0,
    'this book': 0,
    'this is': 0
}

What is the most efficient way of updating the frequency counts of this dictionary in one pass of the input string (if it is possible)? I get a feeling that there must be a parser technique to do this but am not an expert in this area so am stuck. Any suggestions?

Answer 1

Check out the Aho-Corasick algorithm.