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

   1 // -*- C++ -*-
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   3 // Copyright (C) 2005, 2006 Free Software Foundation, Inc.
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   8 // Foundation; either version 2, or (at your option) any later
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  14 // General Public License for more details.
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  21 // As a special exception, you may use this file as part of a free
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  29 // Public License.
  30
  31 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
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  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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  41
  42 /**
  43  * @file priority_queue_split_join_example.cpp
  44  * A basic example showing how to split and join priority queues.
  45  */
  46
  47 /**
  48  * This example shows how to split and join priority queues.
  49  */
  50
  51 #include <functional>
  52 #include <iostream>
  53 #include <cassert>
  54 #include <ext/pb_ds/priority_queue.hpp>
  55
  56 using namespace std;
  57 using namespace __gnu_pbds;
  58
  59 int
  60 main()
  61 {
  62   // Two priority queue objects.
  63   __gnu_pbds::priority_queue<int> even_p, odd_p;
  64
  65   // First we insert some values: even ones into even_p, and odd ones
  66   // into odd_p.
  67   for (size_t i = 0; i < 10; ++i)
  68     {
  69       even_p.push(2*  i);
  70       odd_p.push(2*  i + 1);
  71     }
  72
  73   // Check that each one contains the appropriate 10 values.
  74   assert(even_p.size() == 10);
  75   assert(even_p.top() == 18);
  76
  77   // Print out the values.
  78   cout << "Initial values in even priority queue:" << endl;
  79   __gnu_pbds::priority_queue<int>::const_iterator it;
  80   for (it = even_p.begin(); it != even_p.end(); ++it)
  81     cout <<* it << endl;
  82
  83   assert(odd_p.size() == 10);
  84   assert(odd_p.top() == 19);
  85
  86   // Print out the values.
  87   cout << "Initial values in odd priority queue:" << endl;
  88   for (it = odd_p.begin(); it != odd_p.end(); ++it)
  89     cout <<* it << endl;
  90
  91   // Now join the queues.
  92   even_p.join(odd_p);
  93
  94   // Check that each one contains the appropriate values.
  95
  96   assert(even_p.size() == 20);
  97   assert(even_p.top() == 19);
  98
  99   // Print out the values.
 100   cout << "After-join values in even priority queue:" << endl;
 101   for (it = even_p.begin(); it != even_p.end(); ++it)
 102     cout <<* it << endl;
 103
 104   assert(odd_p.size() == 0);
 105
 106   // Print out the values.
 107   cout << "After-join values in odd priority queue:" << endl;
 108   for (it = odd_p.begin(); it != odd_p.end(); ++it)
 109     cout <<* it << endl;
 110
 111   // Now split the queues.
 112   even_p.split(bind2nd(modulus<int>(), 2), odd_p);
 113
 114   // Check that each one contains the appropriate 10 values.
 115
 116   assert(even_p.size() == 10);
 117   assert(even_p.top() == 18);
 118
 119   // Print out the values.
 120   cout << "After-split values in even priority queue:" << endl;
 121   for (it = even_p.begin(); it != even_p.end(); ++it)
 122     cout <<* it << endl;
 123
 124   assert(odd_p.size() == 10);
 125   assert(odd_p.top() == 19);
 126
 127   // Print out the values.
 128   cout << "After-split values in odd priority queue:" << endl;
 129   for (it = odd_p.begin(); it != odd_p.end(); ++it)
 130     cout <<* it << endl;
 131
 132   return 0;
 133 }
 134