/*
    $Id: jd.cc 1109 2007-04-17 00:04:26Z rvernica $

    Copyright (C) 2007 by The Regents of the University of California

    Redistribution of this file is permitted under the terms of the
    GNU Public License (GPL).

    Date: 03/24/2007
    Author: Rares Vernica <rvernica@ics.uci.edu>
*/

#include "jd.h"

#include <algorithm>

#include "gram.h"

using namespace std;

float jd(const string &s1, const string &s2, const unsigned q)
{
  unsigned
    n = s1.length(), 
    m = s2.length();

  if (n == 0 || m == 0)
    return 1;

  set<string> s1Gram, s2Gram, sInt, sUni;
  str2grams(s1, s1Gram, q);
  str2grams(s2, s2Gram, q);

  set_intersection(s1Gram.begin(), s1Gram.end(),
                   s2Gram.begin(), s2Gram.end(), 
                   inserter(sInt, sInt.begin()));

  set_union(s1Gram.begin(), s1Gram.end(),
            s2Gram.begin(), s2Gram.end(), 
            inserter(sUni, sUni.begin()));

  return 1 - static_cast<float>(sInt.size()) / sUni.size();
}