C++ Tutorial/STL Algorithms Heap/push heap — различия между версиями
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Текущая версия на 10:29, 25 мая 2010
Sort vector1 using push_heap and pop_heap
#include <iostream>
#include <cassert>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
vector<int> vector1(5);
for (int i = 0; i < 5; ++i)
vector1[i] = i;
random_shuffle(vector1.begin(), vector1.end());
for (int i = 2; i <= 5; ++i)
push_heap(vector1.begin(), vector1.begin() + i);
for (int i = 5; i >= 2; --i)
pop_heap(vector1.begin(), vector1.begin() + i);
for (int i = 0; i < 5; ++i)
cout << vector1[i];
return 0;
}01234
Use push_heap to push new element into the heap
/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
}
/* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
}
using namespace std;
int main()
{
vector<int> coll;
INSERT_ELEMENTS(coll,3,7);
INSERT_ELEMENTS(coll,5,9);
INSERT_ELEMENTS(coll,1,4);
PRINT_ELEMENTS (coll, "on entry: ");
// convert collection into a heap
make_heap (coll.begin(), coll.end());
PRINT_ELEMENTS (coll, "after make_heap(): ");
// push new element into the heap
coll.push_back (17);
push_heap (coll.begin(), coll.end());
PRINT_ELEMENTS (coll, "after push_heap(): ");
}on entry: 3 4 5 6 7 5 6 7 8 9 1 2 3 4 after make_heap(): 9 8 6 7 7 5 5 3 6 4 1 2 3 4 after push_heap(): 17 8 9 7 7 5 6 3 6 4 1 2 3 4 5
