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Longest increasing subsequence: Difference between revisions
→{{header|C++}}
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=={{header|C++}}==
Patience sorting
=== C++11 ===
<lang cpp>#include <vector>
#include <list>
Line 488 ⟶ 489:
show_lis(std::vector<int> { 0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15 });
}</lang>
=== C++98 ===
<lang cpp>#include <vector>
#include <list>
#include <algorithm>
#include <iostream>
template <typename T>
struct Node {
T value;
Node* prev_node;
};
template <typename T>
bool compare (const T& node1, const T& node2)
{
return node1->value < node2->value;
}
template <typename Container>
Container lis(const Container& values) {
typedef typename Container::value_type E;
typedef typename Container::const_iterator ValueConstIter;
typedef typename Container::iterator ValueIter;
typedef Node<E>* NodePtr;
typedef const NodePtr ConstNodePtr;
typedef std::vector<Node<E> > NodeVector;
typedef std::vector<NodePtr> NodePtrVector;
typedef typename NodeVector::iterator NodeVectorIter;
typedef typename NodePtrVector::iterator NodePtrVectorIter;
std::vector<NodePtr> pileTops;
std::vector<Node<E> > nodes(values.size());
// sort into piles
NodeVectorIter cur_node = nodes.begin();
for (ValueConstIter cur_value = values.begin(); cur_value != values.end(); ++cur_value, ++cur_node)
{
NodePtr node = &*cur_node;
node->value = *cur_value;
// lower_bound returns the first element that is not less than 'node->value'
NodePtrVectorIter lb = std::lower_bound(pileTops.begin(), pileTops.end(), node, compare<NodePtr>);
if (lb != pileTops.begin())
node->prev_node = *(lb - 1);
if (lb == pileTops.end())
pileTops.push_back(node);
else
*lb = node;
}
// extract LIS from piles
// note that LIS length is equal to the number of piles
Container result(pileTops.size());
std::reverse_iterator<ValueIter> r = std::reverse_iterator<ValueIter>(result.rbegin());
for (NodePtr node = pileTops.back(); node; node = node->prev_node, ++r)
*r = node->value;
return result;
}
template <typename Container>
void show_lis(const Container& values)
{
const Container& result = lis(values);
for (typename Container::const_iterator it = result.begin(); it != result.end(); ++it) {
std::cout << *it << ' ';
}
std::cout << std::endl;
}
int main()
{
const int arr1[] = { 3, 2, 6, 4, 5, 1 };
const int arr2[] = { 0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15 };
std::vector<int> vec1(arr1, arr1 + sizeof(arr1) / sizeof(arr1[0]));
std::vector<int> vec2(arr2, arr2 + sizeof(arr2) / sizeof(arr2[0]));
show_lis(vec1);
show_lis(vec2);
}</lang>
{{out}}
<pre>2 4 5
0 2 6 9 11 15 </pre>
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