Difference between revisions of "cpp/algorithm/ranges/pop heap"
From cppreference.com
m (mathjax-or) |
Andreas Krug (Talk | contribs) m (fmt) |
||
| Line 2: | Line 2: | ||
{{cpp/algorithm/ranges/navbar}} | {{cpp/algorithm/ranges/navbar}} | ||
{{dcl begin}} | {{dcl begin}} | ||
| − | {{dcl header | algorithm}} | + | {{dcl header|algorithm}} |
{{dcl h|Call signature}} | {{dcl h|Call signature}} | ||
| − | {{dcl | num=1 | since=c++20 |1= | + | {{dcl|num=1|since=c++20|1= |
template< std::random_access_iterator I, std::sentinel_for<I> S, | template< std::random_access_iterator I, std::sentinel_for<I> S, | ||
class Comp = ranges::less, class Proj = std::identity > | class Comp = ranges::less, class Proj = std::identity > | ||
requires std::sortable<I, Comp, Proj> | requires std::sortable<I, Comp, Proj> | ||
constexpr I | constexpr I | ||
| − | pop_heap( I first, S last, Comp comp = {}, Proj proj = {} ); | + | pop_heap( I first, S last, Comp comp = {}, Proj proj = {} ); |
}} | }} | ||
| − | {{dcl | num=2 | since=c++20 |1= | + | {{dcl|num=2|since=c++20|1= |
template< ranges::random_access_range R, class Comp = ranges::less, | template< ranges::random_access_range R, class Comp = ranges::less, | ||
class Proj = std::identity > | class Proj = std::identity > | ||
requires std::sortable<ranges::iterator_t<R>, Comp, Proj> | requires std::sortable<ranges::iterator_t<R>, Comp, Proj> | ||
constexpr ranges::borrowed_iterator_t<R> | constexpr ranges::borrowed_iterator_t<R> | ||
| − | pop_heap( R&& r, Comp comp = {}, Proj proj = {} ); | + | pop_heap( R&& r, Comp comp = {}, Proj proj = {} ); |
}} | }} | ||
{{dcl end}} | {{dcl end}} | ||
| − | Swaps the value in the position {{ | + | Swaps the value in the position {{c|first}} and the value in the position {{c|last - 1}} and makes the subrange {{range|first|last - 1}} into a [[enwiki:Binary_heap|''max heap'']]. This has the effect of removing the first element from the heap defined by the range {{range|first|last}}. |
| − | @1@ Elements are compared using the given binary comparison function {{ | + | @1@ Elements are compared using the given binary comparison function {{c|comp}} and projection object {{c|proj}}. |
| − | @2@ Same as {{v|1}}, but uses {{ | + | @2@ Same as {{v|1}}, but uses {{c|r}} as the range, as if using {{c|ranges::begin(r)}} as {{c|first}} and {{c|ranges::end(r)}} as {{c|last}}. |
{{cpp/ranges/niebloid}} | {{cpp/ranges/niebloid}} | ||
| Line 30: | Line 30: | ||
===Parameters=== | ===Parameters=== | ||
{{par begin}} | {{par begin}} | ||
| − | {{par | first, last | the range of elements defining the valid nonempty heap to modify}} | + | {{par|first, last|the range of elements defining the valid nonempty heap to modify}} |
| − | {{par | r | + | {{par|r|the range of elements defining the valid nonempty heap to modify}} |
| − | {{par | pred | + | {{par|pred|predicate to apply to the projected elements}} |
| − | {{par | proj | + | {{par|proj|projection to apply to the elements}} |
{{par end}} | {{par end}} | ||
===Return value=== | ===Return value=== | ||
| − | An iterator equal to {{ | + | An iterator equal to {{c|last}}. |
===Complexity=== | ===Complexity=== | ||
| Line 53: | Line 53: | ||
#include <string_view> | #include <string_view> | ||
| − | template <class I = int*> | + | template<class I = int*> |
void print(std::string_view rem, I first = {}, I last = {}, | void print(std::string_view rem, I first = {}, I last = {}, | ||
std::string_view term = "\n") | std::string_view term = "\n") | ||
{ | { | ||
| − | for (std::cout << rem; first != last; ++first) | + | for (std::cout << rem; first != last; ++first) |
std::cout << *first << ' '; | std::cout << *first << ' '; | ||
| − | |||
std::cout << term; | std::cout << term; | ||
} | } | ||
| Line 65: | Line 64: | ||
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()); | ||
| Line 72: | Line 71: | ||
print("convert heap into sorted array:"); | print("convert heap into sorted array:"); | ||
| − | for (auto n {std::ssize(v)}; n >= 0; --n) { | + | for (auto n {std::ssize(v)}; n >= 0; --n) |
| + | { | ||
std::ranges::pop_heap(v.begin(), v.begin() + n); | std::ranges::pop_heap(v.begin(), v.begin() + n); | ||
print("[ ", v.cbegin(), v.cbegin() + n, "] "); | print("[ ", v.cbegin(), v.cbegin() + n, "] "); | ||
| Line 78: | Line 78: | ||
} | } | ||
} | } | ||
| − | | output= | + | |output= |
initially, v: 3 1 4 1 5 9 2 6 5 3 | 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 | make_heap, v: 9 6 4 5 5 3 2 1 1 3 | ||
| Line 97: | Line 97: | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/algorithm/ranges/dsc push_heap}} | + | {{dsc inc|cpp/algorithm/ranges/dsc push_heap}} |
| − | {{dsc inc | cpp/algorithm/ranges/dsc is_heap}} | + | {{dsc inc|cpp/algorithm/ranges/dsc is_heap}} |
| − | {{dsc inc | cpp/algorithm/ranges/dsc is_heap_until}} | + | {{dsc inc|cpp/algorithm/ranges/dsc is_heap_until}} |
| − | {{dsc inc | cpp/algorithm/ranges/dsc make_heap}} | + | {{dsc inc|cpp/algorithm/ranges/dsc make_heap}} |
| − | {{dsc inc | cpp/algorithm/ranges/dsc sort_heap}} | + | {{dsc inc|cpp/algorithm/ranges/dsc sort_heap}} |
| − | {{dsc inc | cpp/algorithm/dsc pop_heap}} | + | {{dsc inc|cpp/algorithm/dsc pop_heap}} |
{{dsc end}} | {{dsc end}} | ||
{{langlinks|de|es|fr|it|ja|pt|ru|zh}} | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | ||
Revision as of 03:54, 15 April 2023
| Defined in header <algorithm>
|
||
| Call signature |
||
| 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 value in the position first and the value in the position last - 1 and makes the subrange [first, last - 1) into a max heap. This has the effect of removing the first element from the heap defined by the range [first, last).
1) Elements are compared using the given binary comparison function comp and projection object proj.
2) Same as (1), but uses r as the range, as if using ranges::begin(r) as first and ranges::end(r) as 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 |
Parameters
| first, last | - | the range of elements defining the valid nonempty heap to modify |
| r | - | the range of elements defining the valid nonempty heap to modify |
| pred | - | predicate to apply to the projected elements |
| proj | - | projection to apply to the elements |
Return value
An iterator equal to last.
Complexity
Given N = ranges::distance(first, last), at most 2log(N) comparisons and 4log(N) projections.
Notes
Example
Run this code
#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 ]
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) |
