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完成is_heap

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This commit is contained in:
邹晓航
2014-10-14 13:47:03 +08:00
parent 88e63ddec2
commit e4b93ed49c
1 changed files with 40 additions and 17 deletions
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57
TinySTL/Algorithm.h
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@@ -5,6 +5,7 @@
namespace TinySTL{
//********* [fill] ********************
//********* [Algorithm Complexity: O(N)] ****************
template<class ForwardIterator, class T>
void fill(ForwardIterator first, ForwardIterator last, const T& value)
{
@@ -20,6 +21,7 @@ namespace TinySTL{
memset(first, static_cast<unsigned char>(value), (last - first) * sizeof(wchar_t));
}
//********* [fill_n] ********************
//********* [Algorithm Complexity: O(N)] ****************
template<class OutputIterator, class Size, class T>
OutputIterator fill_n(OutputIterator first, Size n, const T& value)
{
@@ -40,6 +42,7 @@ namespace TinySTL{
return first + n;
}
//************ [find] ****************
//********* [Algorithm Complexity: O(N)] ****************
template<class InputIterator, class T>
InputIterator find(InputIterator first, InputIterator last, const T& val){
for (; first != last; ++first){
@@ -49,6 +52,7 @@ namespace TinySTL{
return first;
}
//*********** [min] ********************
//********* [Algorithm Complexity: O(1)] ****************
template <class T>
const T& min(const T& a, const T& b){
return !(b < a) ? a : b;
@@ -58,6 +62,7 @@ namespace TinySTL{
return !comp(b, a) ? a : b;
}
//*********** [max] ********************
//********* [Algorithm Complexity: O(1)] ****************
template <class T>
const T& max(const T& a, const T& b){
return (a < b) ? b : a;
@@ -67,7 +72,9 @@ namespace TinySTL{
return (copm(a, b)) ? b : a;
}
//********** [make_heap] ***************
//********* [Algorithm Complexity: O(N)] ****************
template<class RandomAccessIterator, class Compare>
//heap<61><70><EFBFBD><EFBFBD><EFBFBD>㷨
static void up(RandomAccessIterator first, RandomAccessIterator last, Compare comp){//[first, last]
if (first != last){
auto range = last - first + 1;
@@ -80,20 +87,21 @@ namespace TinySTL{
}
}
template<class RandomAccessIterator, class Compare>
static void down(RandomAccessIterator first, RandomAccessIterator last, Compare comp){//[first, last]
//heap<61>½<EFBFBD><C2BD>㷨
static void down(RandomAccessIterator first, RandomAccessIterator last,
RandomAccessIterator head, Compare comp){//1.[first, last], 2.headr points the header of the heap
if (first != last){
decltype(last - first) range = 1;
for (auto cur = first; cur < last;range = cur - first + 1){
auto child = first + (range * 2 - 1);//get the left child
if (child <= last){
if ((child + 1) <= last && *(child + 1) > *child)
child = child + 1;//right child
if (comp(*cur, *child))
TinySTL::swap(*cur, *child);
cur = child;
}
else
break;
const auto range = last - head + 1;
auto index = first - head;
auto leftChildIndex = index * 2 + 1;
for (auto cur = first; leftChildIndex < range && cur < last; leftChildIndex = index * 2 + 1){
auto child = head + leftChildIndex;//get the left child
if ((child + 1) <= last && *(child + 1) > *child)//cur has a right child
child = child + 1;
if (comp(*cur, *child))
TinySTL::swap(*cur, *child);
cur = child;
index = cur - head;
}
}
}
@@ -105,8 +113,9 @@ namespace TinySTL{
template <class RandomAccessIterator, class Compare>
void make_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp){
const auto range = last - first;
for (auto rait = first + range - 1; rait > first; --rait){
down(first, rait, comp);
for (auto cur = first + range / 2 - 1; cur >= first; --cur){
down(cur, last - 1, first, comp);
if (cur == first) return;
}
}
//********* [push_heap] ***************
@@ -126,9 +135,23 @@ namespace TinySTL{
void sort_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
//********* [is_heap] ***************
template <class RandomAccessIterator>
bool is_heap(RandomAccessIterator first, RandomAccessIterator last);
bool is_heap(RandomAccessIterator first, RandomAccessIterator last){
return TinySTL::is_heap(first, last,
TinySTL::less<typename TinySTL::iterator_traits<RandomAccessIterator>::value_type>());
}
template <class RandomAccessIterator, class Compare>
bool is_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp);
bool is_heap(RandomAccessIterator first, RandomAccessIterator last, Compare comp){
const auto range = last - first;
auto index = range / 2 - 1;
for (auto cur = first + range / 2 - 1; cur >= first; --cur, --index){
if (*(first + (index * 2 + 1)) > *cur ||//left child > cur
((first + (index * 2 + 2)) <= last && *(first + (index * 2 + 2)) > *cur))//right child > cur
return false;
if (cur == first)
break;
}
return true;
}
}