BAN: Move heap functions to Heap.h
This also adds push_heap and pop_heap, similar to what C++ standard library provides
This commit is contained in:
parent
9d3ea6fed7
commit
7f8ea6b8e0
|
|
@ -0,0 +1,90 @@
|
|||
#pragma once
|
||||
|
||||
#include <BAN/Iteration.h>
|
||||
#include <BAN/Swap.h>
|
||||
#include <BAN/Traits.h>
|
||||
#include <cstddef>
|
||||
|
||||
namespace BAN
|
||||
{
|
||||
|
||||
namespace detail
|
||||
{
|
||||
|
||||
template<typename It, typename Comp>
|
||||
void heapify_up(It begin, size_t index, Comp comp)
|
||||
{
|
||||
size_t parent = (index - 1) / 2;
|
||||
while (parent < index)
|
||||
{
|
||||
if (comp(*(begin + index), *(begin + parent)))
|
||||
break;
|
||||
swap(*(begin + parent), *(begin + index));
|
||||
index = parent;
|
||||
parent = (index - 1) / 2;
|
||||
}
|
||||
}
|
||||
|
||||
template<typename It, typename Comp>
|
||||
void heapify_down(It begin, size_t index, size_t len, Comp comp)
|
||||
{
|
||||
for (;;)
|
||||
{
|
||||
const size_t lchild = 2 * index + 1;
|
||||
const size_t rchild = 2 * index + 2;
|
||||
|
||||
size_t child = 0;
|
||||
if (lchild < len && !comp(*(begin + lchild), *(begin + index)))
|
||||
{
|
||||
if (rchild < len && !comp(*(begin + rchild), *(begin + lchild)))
|
||||
child = rchild;
|
||||
else
|
||||
child = lchild;
|
||||
}
|
||||
else if (rchild < len && !comp(*(begin + rchild), *(begin + index)))
|
||||
child = rchild;
|
||||
else
|
||||
break;
|
||||
|
||||
swap(*(begin + child), *(begin + index));
|
||||
index = child;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>>
|
||||
void make_heap(It begin, It end, Comp comp = {})
|
||||
{
|
||||
const size_t len = distance(begin, end);
|
||||
if (len <= 1)
|
||||
return;
|
||||
|
||||
size_t index = (len - 2) / 2;
|
||||
while (index < len)
|
||||
detail::heapify_down(begin, index--, len, comp);
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>>
|
||||
void push_heap(It begin, It end, Comp comp = {})
|
||||
{
|
||||
const size_t len = distance(begin, end);
|
||||
detail::heapify_up(begin, len - 1, comp);
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>>
|
||||
void pop_heap(It begin, It end, Comp comp = {})
|
||||
{
|
||||
const size_t len = distance(begin, end);
|
||||
swap(*begin, *(begin + len - 1));
|
||||
detail::heapify_down(begin, 0, len - 1, comp);
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>>
|
||||
void sort_heap(It begin, It end, Comp comp = {})
|
||||
{
|
||||
while (begin != end)
|
||||
pop_heap(begin, end--, comp);
|
||||
}
|
||||
|
||||
}
|
||||
|
|
@ -1,5 +1,6 @@
|
|||
#pragma once
|
||||
|
||||
#include <BAN/Heap.h>
|
||||
#include <BAN/Math.h>
|
||||
#include <BAN/Swap.h>
|
||||
#include <BAN/Traits.h>
|
||||
|
|
@ -67,82 +68,6 @@ namespace BAN::sort
|
|||
}
|
||||
}
|
||||
|
||||
namespace detail
|
||||
{
|
||||
|
||||
template<typename It, typename Comp>
|
||||
void push_heap(It begin, size_t hole_index, size_t top_index, it_value_type_t<It> value, Comp comp)
|
||||
{
|
||||
size_t parent = (hole_index - 1) / 2;
|
||||
while (hole_index > top_index && comp(*next(begin, parent), value))
|
||||
{
|
||||
*next(begin, hole_index) = move(*next(begin, parent));
|
||||
hole_index = parent;
|
||||
parent = (hole_index - 1) / 2;
|
||||
}
|
||||
*next(begin, hole_index) = move(value);
|
||||
}
|
||||
|
||||
template<typename It, typename Comp>
|
||||
void adjust_heap(It begin, size_t hole_index, size_t len, it_value_type_t<It> value, Comp comp)
|
||||
{
|
||||
const size_t top_index = hole_index;
|
||||
size_t child = hole_index;
|
||||
while (child < (len - 1) / 2)
|
||||
{
|
||||
child = 2 * (child + 1);
|
||||
if (comp(*next(begin, child), *next(begin, child - 1)))
|
||||
child--;
|
||||
*next(begin, hole_index) = move(*next(begin, child));
|
||||
hole_index = child;
|
||||
}
|
||||
if (len % 2 == 0 && child == (len - 2) / 2)
|
||||
{
|
||||
child = 2 * (child + 1);
|
||||
*next(begin, hole_index) = move(*next(begin, child - 1));
|
||||
hole_index = child - 1;
|
||||
}
|
||||
push_heap(begin, hole_index, top_index, move(value), comp);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>
|
||||
void make_heap(It begin, It end, Comp comp = {})
|
||||
{
|
||||
const size_t len = distance(begin, end);
|
||||
if (len <= 1)
|
||||
return;
|
||||
|
||||
size_t parent = (len - 2) / 2;
|
||||
while (true)
|
||||
{
|
||||
detail::adjust_heap(begin, parent, len, move(*next(begin, parent)), comp);
|
||||
|
||||
if (parent == 0)
|
||||
break;
|
||||
|
||||
parent--;
|
||||
}
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>>
|
||||
void sort_heap(It begin, It end, Comp comp = {})
|
||||
{
|
||||
const size_t len = distance(begin, end);
|
||||
if (len <= 1)
|
||||
return;
|
||||
|
||||
size_t last = len;
|
||||
while (last > 1)
|
||||
{
|
||||
last--;
|
||||
typename It::value_type x = move(*next(begin, last));
|
||||
*next(begin, last) = move(*begin);
|
||||
detail::adjust_heap(begin, 0, last, move(x), comp);
|
||||
}
|
||||
}
|
||||
|
||||
template<typename It, typename Comp = less<it_value_type_t<It>>>
|
||||
void heap_sort(It begin, It end, Comp comp = {})
|
||||
{
|
||||
|
|
|
|||
Loading…
Reference in New Issue