// -*- C++ -*- // Copyright (C) 2005, 2006 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 2, 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 COPYING. If not, write to // the Free Software Foundation, 59 Temple Place - Suite 330, Boston, // MA 02111-1307, USA. // As a special exception, you may use this file as part of a free // software library without restriction. Specifically, if other files // instantiate templates or use macros or inline functions from this // file, or you compile this file and link it with other files to // produce an executable, this file does not by itself cause the // resulting executable to be covered by the GNU General Public // License. This exception does not however invalidate any other // reasons why the executable file might be covered by the GNU General // Public License. // 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 pb_ds; using namespace pb_ds; // 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_mapped_type mapped_type; typedef string_trie_e_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; }