Defined in header <algorithm> | ||
---|---|---|
template< class RandomIt > void push_heap( RandomIt first, RandomIt last ); | (1) | |
template< class RandomIt, class Compare > void push_heap( RandomIt first, RandomIt last, Compare comp ); | (2) |
Inserts the element at the position last-1
into the max heap defined by the range [first, last-1)
. The first version of the function uses operator<
to compare the elements, the second uses the given comparison function comp
.
Parameters
first, last | - | the range of elements defining the heap to modify |
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:
The signature does not need to have |
Type requirements | ||
- RandomIt must meet the requirements of RandomAccessIterator . | ||
-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible . |
Return value
(none).
Complexity
At most 2×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 <iostream> #include <algorithm> #include <vector> int main() { std::vector<int> v { 3, 1, 4, 1, 5, 9 }; std::make_heap(v.begin(), v.end()); std::cout << "v: "; for (auto i : v) std::cout << i << ' '; std::cout << '\n'; v.push_back(6); std::cout << "before push_heap: "; for (auto i : v) std::cout << i << ' '; std::cout << '\n'; std::push_heap(v.begin(), v.end()); std::cout << "after push_heap: "; for (auto i : v) std::cout << i << ' '; std::cout << '\n'; }
Output:
v: 9 5 4 1 1 3 before push_heap: 9 5 4 1 1 3 6 after push_heap: 9 5 6 1 1 3 4
See also
removes the largest element from a max heap (function template) | |
creates a max heap out of a range of elements (function template) |
Please login to continue.