C++ Tutorial/STL Algorithms Heap/push heap

Sort vector1 using push_heap and pop_heap

<source lang="cpp">#include <iostream>

1. include <cassert>
2. include <algorithm>
3. 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;

}</source>

01234

Use push_heap to push new element into the heap

<source lang="cpp">/* 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.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. 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():  ");

}</source>

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