push_heap() in C++ STL

The C++ Standard Library consists of the header, <algorithm> which defines a collection of functions (principally designed to deal with a range of elements). push_heap() is a method in the STL that is used to insert an element into the heap. The size of the heap effectively increases by one.

Syntax:

push_heap( iterator_begin, iterator_end, comparator ); //comparator is optional

Parameters: The push_heap() method accepts 3 parameters

• iterator_begin: Iterator to the initial position of new heap
• iterator_end: Iterator to the final position of new heap ( Note: the range is [iterator_begin,iterator_end) )
• comparator: Binary function that accepts two elements in the range as arguments, and returns a value convertible to bool.

Return value: none

Example of push_heap() method

#include<iostream>
#include<algorithm>
#include<vector>

using namespace std;

int main()
{
    vector<int> v;
    v.push_back(4);
    v.push_back(3);
    v.push_back(8);
    v.push_back(-5);
    v.push_back(7);

    make_heap(v.begin(), v.end());
    cout<<"Initial heap: "<<v.front()<<endl; //max val

    v.push_back(12);
    push_heap(v.begin(), v.end());
    cout<<"New heap: "<<v.front()<<endl; //max val
}

Output:

Initial heap: 8
New heap: 12