std::push_heap
Defined in header
<algorithm>
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template< class RandomIt >
void push_heap( RandomIt first, RandomIt last ); |
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template< class RandomIt, class Compare >
void push_heap( RandomIt first, RandomIt last, |
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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
.
Contents |
[edit] 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: 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. |
Type requirements | ||
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RandomIt must meet the requirements of RandomAccessIterator .
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-The type of dereferenced RandomIt must meet the requirements of MoveAssignable and MoveConstructible .
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[edit] Return value
(none)
[edit] Complexity
At most 2×log(N) comparisons where N=std::distance(first, last).
[edit] 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.
[edit] 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
[edit] See also
removes the largest element from a max heap (function template) |
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creates a max heap out of a range of elements (function template) |