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/***************************************************************************
* examples/containers/pqueue2.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)
**************************************************************************/
#include <stxxl/priority_queue>
#include <limits>
// comparison struct for priority queue where top() returns the biggest contained value:
struct Cmp
{
bool operator () (const int& a, const int& b) const
{ return a < b; }
int min_value() const
{ return std::numeric_limits<int>::min(); }
};
int main()
{
// use 64 GiB on main memory and 1 billion items at most
typedef stxxl::PRIORITY_QUEUE_GENERATOR<int, Cmp, 64*1024*1024, 1024*1024>::result pq_type;
typedef pq_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);
pq_type Q(pool);
Q.push(1);
Q.push(4);
Q.push(2);
Q.push(8);
Q.push(5);
Q.push(7);
assert(Q.size() == 6);
assert(Q.top() == 8);
Q.pop();
assert(Q.top() == 7);
Q.pop();
assert(Q.top() == 5);
Q.pop();
assert(Q.top() == 4);
Q.pop();
assert(Q.top() == 2);
Q.pop();
assert(Q.top() == 1);
Q.pop();
assert(Q.empty());
return 0;
}
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