Perform the heapsort with push_heap and pop_heap - C++ STL Algorithm

C++ examples for STL Algorithm:push_heap

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Description

Perform the heapsort with push_heap and pop_heap

Demo Code

#include <iostream> 
#include <algorithm> 
#include <vector> 
#include <iterator> 
using namespace std; 

int main() // w  ww  .j a v a2  s. com
{ 
   const int SIZE = 10; 
   int a[ SIZE ] = { 3, 100, 52, 77, 22, 31, 1, 98, 13, 40 }; 
   vector< int > v( a, a + SIZE ); // copy of a 
   vector< int > v2; 
   ostream_iterator< int > output( cout, " " ); 

   cout << "Vector v before make_heap:\n"; 
   copy( v.begin(), v.end(), output ); 

   make_heap( v.begin(), v.end() ); // create heap from vector v 
   cout << "\nVector v after make_heap:\n" ; 
   copy( v.begin(), v.end(), output ); 

   // perform the heapsort with push_heap and pop_heap 
   cout << "\n\nArray a contains: "; 
   copy( a, a + SIZE, output ); // display array a 
   cout << endl; 

   // place elements of array a into v2 and 
   // maintain elements of v2 in heap 
    for ( int i = 0; i < SIZE; ++i ) 
    { 
       v2 .push_back( a[ i ] ); 
       push_heap( v2 .begin(), v2.end() ); 
       cout << "\nv2 after push_heap(a[" << i << "]): "; 
       copy( v2.begin(), v2 .end(), output ); 
    }

   cout << endl; 

   // remove elements from heap in sorted order 
   for ( unsigned int j = 0; j < v2.size(); ++j ) 
   { 
       cout << "\nv2 after " << v2[ 0 ] << " popped from heap\n"; 
       pop_heap( v2.begin(), v2.end() - j ); 
       copy( v2.begin(), v2 .end(), output ); 
   }

   cout << endl; 
}

Result


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