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/***************************************************************************
* examples/containers/pqueue1.cpp
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2013 Daniel Feist <daniel.feist@student.kit.edu>
*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
**************************************************************************/
//! [example]
#include <stxxl/priority_queue>
#include <iostream>
#include <limits>
// comparison struct for priority queue where top() returns the smallest contained value:
struct ComparatorGreater
{
bool operator () (const int& a, const int& b) const
{ return (a > b); }
int min_value() const
{ return std::numeric_limits<int>::max(); }
};
int main()
{
typedef stxxl::PRIORITY_QUEUE_GENERATOR<int, ComparatorGreater, 128*1024*1024, 1024*1024>::result pqueue_type;
typedef pqueue_type::block_type block_type;
// block_type::raw_size = 262144 bytes
// use 64 block read and write pools each to enable overlapping between I/O and computation
const unsigned int mem_for_pools = 32 * 1024 * 1024;
stxxl::read_write_pool<block_type> pool((mem_for_pools / 2) / block_type::raw_size, (mem_for_pools / 2) / block_type::raw_size);
pqueue_type my_pqueue(pool); // creates stxxl priority queue instance with read-write-pool
my_pqueue.push(5);
my_pqueue.push(4);
my_pqueue.push(19);
my_pqueue.push(1);
assert(my_pqueue.size() == 4);
assert(my_pqueue.top() == 1);
STXXL_MSG("Smallest inserted value in my: " << my_pqueue.top());
my_pqueue.pop(); // pop the 1 on top
assert(my_pqueue.top() == 4);
STXXL_MSG("Smallest value after 1 pop(): " << my_pqueue.top());
return 0;
}
//! [example]
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