C++ Tutorial/STL Algorithms Heap/pop heap

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Demonstrating push_heap, pop_heap, make_heap and sort_heap.

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main(){
   const int SIZE = 10;
   int a[ SIZE ] = { 3, 100, 52, 77, 22, 31, 1, 98, 13, 40 };
   int i;
   vector< int > v( a, a + SIZE ), v2;
   make_heap( v.begin(), v.end() );
   sort_heap( v.begin(), v.end() );
   for ( i = 0; i < SIZE; ++i ) {
      v2.push_back( a[ i ] );
      push_heap( v2.begin(), v2.end() );      
   }
   
   for ( i = 0; i < v2.size(); ++i ) {
      cout << "\nv2 after " << v2[ 0 ] << " popped from heap\n";
      pop_heap( v2.begin(), v2.end() - i );
   }
   cout << endl;
   return 0;
}

Use pop_heap to pop next element out of 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():  ");
    // pop next element out of the heap
    pop_heap (coll.begin(), coll.end());
    coll.pop_back();
    PRINT_ELEMENTS (coll, "after pop_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 pop_heap():   8 7 6 7 4 5 5 3 6 4 1 2 3
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