Difference between revisions of "cpp/algorithm/ranges/pop heap"
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int main() | int main() | ||
{ | { | ||
| − | std::array v {3, 1, 4, 1, 5, 9, 2, 6, 5, 3}; | + | std::array v{3, 1, 4, 1, 5, 9, 2, 6, 5, 3}; |
print("initially, v: ", v.cbegin(), v.cend()); | print("initially, v: ", v.cbegin(), v.cend()); | ||
Latest revision as of 01:23, 14 October 2024
| Defined in header <algorithm>
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| Call signature |
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| template< std::random_access_iterator I, std::sentinel_for<I> S, class Comp = ranges::less, class Proj = std::identity > |
(1) | (since C++20) |
| template< ranges::random_access_range R, class Comp = ranges::less, class Proj = std::identity > |
(2) | (since C++20) |
Swaps the first element and the last element of the specified heap with respect to comp and proj and makes the subrange excluding the first position into a heap with respect to comp and proj. This has the effect of removing the first element from the specified heap.
[first, last).The function-like entities described on this page are niebloids, that is:
- Explicit template argument lists cannot be specified when calling any of them.
- None of them are visible to argument-dependent lookup.
- When any of them are found by normal unqualified lookup as the name to the left of the function-call operator, argument-dependent lookup is inhibited.
In practice, they may be implemented as function objects, or with special compiler extensions.
Contents |
[edit] Parameters
| first, last | - | the iterator and sentinel designating the range of elements to modify |
| r | - | the range of elements to modify |
| comp | - | comparator to apply to the projected elements |
| proj | - | projection to apply to the elements |
[edit] Return value
[edit] Complexity
At most 2log(N) applications of comp and 4log(N) applications of proj, where N is:
[edit] Example
#include <algorithm> #include <array> #include <iostream> #include <iterator> #include <string_view> template<class I = int*> void print(std::string_view rem, I first = {}, I last = {}, std::string_view term = "\n") { for (std::cout << rem; first != last; ++first) std::cout << *first << ' '; std::cout << term; } int main() { std::array v{3, 1, 4, 1, 5, 9, 2, 6, 5, 3}; print("initially, v: ", v.cbegin(), v.cend()); std::ranges::make_heap(v); print("make_heap, v: ", v.cbegin(), v.cend()); print("convert heap into sorted array:"); for (auto n {std::ssize(v)}; n >= 0; --n) { std::ranges::pop_heap(v.begin(), v.begin() + n); print("[ ", v.cbegin(), v.cbegin() + n, "] "); print("[ ", v.cbegin() + n, v.cend(), "]\n"); } }
Output:
initially, v: 3 1 4 1 5 9 2 6 5 3 make_heap, v: 9 6 4 5 5 3 2 1 1 3 convert heap into sorted array: [ 6 5 4 3 5 3 2 1 1 9 ] [ ] [ 5 5 4 3 1 3 2 1 6 ] [ 9 ] [ 5 3 4 1 1 3 2 5 ] [ 6 9 ] [ 4 3 3 1 1 2 5 ] [ 5 6 9 ] [ 3 2 3 1 1 4 ] [ 5 5 6 9 ] [ 3 2 1 1 3 ] [ 4 5 5 6 9 ] [ 2 1 1 3 ] [ 3 4 5 5 6 9 ] [ 1 1 2 ] [ 3 3 4 5 5 6 9 ] [ 1 1 ] [ 2 3 3 4 5 5 6 9 ] [ 1 ] [ 1 2 3 3 4 5 5 6 9 ] [ ] [ 1 1 2 3 3 4 5 5 6 9 ]
[edit] See also
| (C++20) |
adds an element to a max heap (niebloid) |
| (C++20) |
checks if the given range is a max heap (niebloid) |
| (C++20) |
finds the largest subrange that is a max heap (niebloid) |
| (C++20) |
creates a max heap out of a range of elements (niebloid) |
| (C++20) |
turns a max heap into a range of elements sorted in ascending order (niebloid) |
| removes the largest element from a max heap (function template) |
