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std::sort_heap

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< cpp‎ | algorithm
Revision as of 08:35, 28 March 2013 by Jaredgrubb (Talk | contribs)

 
 
 

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Defined in header <algorithm>
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template< class RandomIt >
void sort_heap( RandomIt first, RandomIt last );
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template< class RandomIt, class Compare >
void sort_heap( RandomIt first, RandomIt last, Compare comp );
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Converts the heap [first, last) into a sorted range in ascending order. The resulting range no longer has the heap property.

The first version of the function uses operator< to compare the elements, the second uses the given comparison function comp.

Contents

Parameters

first, last - the range of elements to sort
comp - comparison function object (i.e. an object that satisfies the requirements of Compare) which returns ​true if the first argument is less than the second.

The signature of the comparison function should be equivalent to the following:

 bool cmp(const Type1 &a, const Type2 &b);

The signature does not need to have const &, but the function object must not modify the objects passed to it.
The types Type1 and Type2 must be such that an object of type RandomIt can be dereferenced and then implicitly converted to both of them. ​

Type requirements
-
RandomIt must meet the requirements of ValueSwappable and RandomAccessIterator.
-
The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible.

Return value

(none)

Complexity

At most N×log(N) comparisons where N=std::distance(first, last).

Notes

A max heap is a range of elements [f,l) that has the following properties:

  • *f is the largest element in the range
  • a new element can be added using std::push_heap()
  • the first element can be removed using std::pop_heap()

The actual arrangement of the elements is implementation defined.

Example

#include <algorithm>
#include <vector>
#include <iostream>
 
int main()
{
    std::vector<int> v = {3, 1, 4, 1, 5, 9}; 
 
    std::make_heap(v.begin(), v.end());
 
    std::cout << "heap:\t";
    for (const auto &i : v) {
        std::cout << i << ' ';
    }   
 
    std::sort_heap(v.begin(), v.end());
 
    std::cout << "\nsorted:\t";
    for (const auto &i : v) {                                                   
        std::cout << i << ' ';
    }   
    std::cout << '\n';
}

Output:

heap:   9 4 5 1 1 3 
sorted: 1 1 3 4 5 9

See also

Template:cpp/algorithm/dcl list make heap