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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005, 2006 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 2, 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 COPYING.  If not, write to
  18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  19 // MA 02111-1307, USA.
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  21 // As a special exception, you may use this file as part of a free
  22 // software library without restriction.  Specifically, if other files
  23 // instantiate templates or use macros or inline functions from this
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  25 // produce an executable, this file does not by itself cause the
  26 // resulting executable to be covered by the GNU General Public
  27 // License.  This exception does not however invalidate any other
  28 // reasons why the executable file might be covered by the GNU General
  29 // Public License.
  30
  31 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  32
  33 // Permission to use, copy, modify, sell, and distribute this software
  34 // is hereby granted without fee, provided that the above copyright
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  40 // warranty.
  41
  42 /**
  43  * @file tree_order_statistics_example.cpp
  44  * An example showing how to use functors for order-statistics
  45  *    in tree-based containers.
  46  */
  47
  48 /**
  49  * In some cases tree structure can be used for various purposes asides
  50  *    from storing entries by key order.
  51  *    This example shows how a tree-based container can be used for
  52  *    order-statistics, i.e., for determining the order of each key
  53  *     in the (ordered) sequence of keys stored within the container object.
  54  */
  55
  56 #include <cassert>
  57 #include <ext/pb_ds/assoc_container.hpp>
  58 #include <ext/pb_ds/tree_policy.hpp>
  59
  60 using namespace std;
  61 using namespace __gnu_pbds;
  62
  63 // A red-black tree table storing ints and their order
  64 // statistics. Note that since the tree uses
  65 // tree_order_statistics_node_update as its update policy, then it
  66 // includes its methods by_order and order_of_key.
  67 typedef
  68 tree<
  69   int,
  70   null_mapped_type,
  71   less<int>,
  72   rb_tree_tag,
  73   // This policy updates nodes' metadata for order statistics.
  74   tree_order_statistics_node_update>
  75 set_t;
  76
  77 int main()
  78 {
  79   // Insert some entries into s.
  80   set_t s;
  81   s.insert(12);
  82   s.insert(505);
  83   s.insert(30);
  84   s.insert(1000);
  85   s.insert(10000);
  86   s.insert(100);
  87
  88   // The order of the keys should be: 12, 30, 100, 505, 1000, 10000.
  89   assert(*s.find_by_order(0) == 12);
  90   assert(*s.find_by_order(1) == 30);
  91   assert(*s.find_by_order(2) == 100);
  92   assert(*s.find_by_order(3) == 505);
  93   assert(*s.find_by_order(4) == 1000);
  94   assert(*s.find_by_order(5) == 10000);
  95   assert(s.find_by_order(6) == s.end());
  96
  97   // The order of the keys should be: 12, 30, 100, 505, 1000, 10000.
  98   assert(s.order_of_key(10) == 0);
  99   assert(s.order_of_key(12) == 0);
 100   assert(s.order_of_key(15) == 1);
 101   assert(s.order_of_key(30) == 1);
 102   assert(s.order_of_key(99) == 2);
 103   assert(s.order_of_key(100) == 2);
 104   assert(s.order_of_key(505) == 3);
 105   assert(s.order_of_key(1000) == 4);
 106   assert(s.order_of_key(10000) == 5);
 107   assert(s.order_of_key(9999999) == 6);
 108
 109   // Erase an entry.
 110   s.erase(30);
 111
 112   // The order of the keys should be: 12, 100, 505, 1000, 10000.
 113   assert(*s.find_by_order(0) == 12);
 114   assert(*s.find_by_order(1) == 100);
 115   assert(*s.find_by_order(2) == 505);
 116   assert(*s.find_by_order(3) == 1000);
 117   assert(*s.find_by_order(4) == 10000);
 118   assert(s.find_by_order(5) == s.end());
 119
 120   // The order of the keys should be: 12, 100, 505, 1000, 10000.
 121   assert(s.order_of_key(10) == 0);
 122   assert(s.order_of_key(12) == 0);
 123   assert(s.order_of_key(100) == 1);
 124   assert(s.order_of_key(505) == 2);
 125   assert(s.order_of_key(707) == 3);
 126   assert(s.order_of_key(1000) == 3);
 127   assert(s.order_of_key(1001) == 4);
 128   assert(s.order_of_key(10000) == 4);
 129   assert(s.order_of_key(100000) == 5);
 130   assert(s.order_of_key(9999999) == 5);
 131
 132   return 0;
 133 }
 134