libstdc++-v3/testsuite/ext/pb_ds/example/trie_split.cc

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2014 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the terms
   7 // of the GNU General Public License as published by the Free Software
   8 // Foundation; either version 3, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20
  21 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  22
  23 // Permission to use, copy, modify, sell, and distribute this software
  24 // is hereby granted without fee, provided that the above copyright
  25 // notice appears in all copies, and that both that copyright notice
  26 // and this permission notice appear in supporting documentation. None
  27 // of the above authors, nor IBM Haifa Research Laboratories, make any
  28 // representation about the suitability of this software for any
  29 // purpose. It is provided "as is" without express or implied
  30 // warranty.
  31
  32 /**
  33  * @file trie_split_example.cpp
  34  * A basic example showing how to split trie-based container objects.
  35  */
  36
  37 /**
  38  * This example shows how to split trie based containers, i.e., the opposite
  39  * of a join operation.
  40  */
  41
  42 #include <string>
  43 #include <cassert>
  44 #include <ext/pb_ds/assoc_container.hpp>
  45
  46 using namespace std;
  47 using namespace __gnu_pbds;
  48
  49 int main()
  50 {
  51   // A PATRICIA trie table mapping strings to chars.
  52   typedef trie<string, char> map_type;
  53
  54   // A map_type object.
  55   map_type r;
  56
  57   // Inserts some entries into r.
  58   for (int i = 0; i < 100; ++ i)
  59     r.insert(make_pair(string(i, 'a'), 'b'));
  60
  61   // Now split r into a different map_type object.
  62
  63   // larger_r will hold the larger values following the split.
  64   map_type larger_r;
  65
  66   // Split all elements with key larger than 'a'^1000 into larger_r.
  67   // This is exception free.
  68   r.split(string(1000, 'a'), larger_r);
  69
  70   // Since there were no elements with key larger than 'a'^1000, r
  71   // should be unchanged.
  72   assert(r.size() == 100);
  73   assert(r.begin()->first == string(""));
  74
  75   // Now perform a split which actually changes the content of r.
  76
  77   // Split all elements with key larger than "aaa" into larger_r.
  78   r.split(string("aaa"), larger_r);
  79
  80   assert(r.size() == 4);
  81   assert(larger_r.begin()->first == string("aaaa"));
  82
  83   return 0;
  84 }
  85