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// -*- C++ -*-

// Copyright (C) 2005, 2006, 2009 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the terms

// of the GNU General Public License as published by the Free Software

// Foundation; either version 3, or (at your option) any later

// version.

// This library is distributed in the hope that it will be useful, but

// WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

// General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with this library; see the file COPYING3.  If not see

// <http://www.gnu.org/licenses/>.

// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software

// is hereby granted without fee, provided that the above copyright

// notice appears in all copies, and that both that copyright notice

// and this permission notice appear in supporting documentation. None

// of the above authors, nor IBM Haifa Research Laboratories, make any

// representation about the suitability of this software for any

// purpose. It is provided "as is" without express or implied

// warranty.

/**

 * @file trie_prefix_search_example.cpp

 * An example showing how to use a trie for searching

 *    for words with a given prefix.

 */

/**

 * This example shows how to use a PATRICIA trie for searching

 * for words with a given prefix.

 */

#include <cassert>

#include <iostream>

#include <ext/pb_ds/assoc_container.hpp>

#include <ext/pb_ds/trie_policy.hpp>

#include <ext/pb_ds/tag_and_trait.hpp>

using namespace std;

using namespace __gnu_pbds;

// A PATRICIA trie with a prefix-search node-updator type. Note that

// since the node updator is trie_prefix_search_node_update, then the

// container includes its method prefix_range.

typedef null_type               mapped_type;

typedef trie_string_access_traits<>     cmp_fn;

typedef pat_trie_tag                    tag_type;

typedef trie<string, mapped_type, cmp_fn, tag_type,

             trie_prefix_search_node_update> trie_type;

// The following helper function takes a trie object and r_key, a

// const reference to a string, and prints all entries whose key

// includes r_key as a prefix.

void

print_prefix_match(const trie_type& t, const string& key)

{

  typedef trie_type::const_iterator             const_iterator;

  typedef pair<const_iterator, const_iterator>  pair_type;

  cout << "All keys whose prefix matches \"" << key << "\":" << endl;

  const pair_type match_range = t.prefix_range(key);

  for (const_iterator it = match_range.first; it != match_range.second; ++it)

    cout << *it << ' ';

  cout << endl;

}

int main()

{

  trie_type t;

  // Insert some entries.

  assert(t.insert("I").second == true);

  assert(t.insert("wish").second == true);

  assert(t.insert("that").second == true);

  assert(t.insert("I").second == false);

  assert(t.insert("could").second == true);

  assert(t.insert("ever").second == true);

  assert(t.insert("see").second == true);

  assert(t.insert("a").second == true);

  assert(t.insert("poem").second == true);

  assert(t.insert("lovely").second == true);

  assert(t.insert("as").second == true);

  assert(t.insert("a").second == false);

  assert(t.insert("trie").second == true);

  // Now search for prefixes.

  print_prefix_match(t, "");

  print_prefix_match(t, "a");

  print_prefix_match(t, "as");

  print_prefix_match(t, "ad");

  print_prefix_match(t, "t");

  print_prefix_match(t, "tr");

  print_prefix_match(t, "trie");

  print_prefix_match(t, "zzz");

  return 0;

}