C++/STL Algorithms Sorting/partial sort copy
Use partial_sort_copy to copy elements in one container sorted into another container
/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
}
/* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
}
using namespace std;
int main()
{
deque<int> coll1;
vector<int> coll6(6); // initialize with 6 elements
vector<int> coll30(30); // initialize with 30 elements
INSERT_ELEMENTS(coll1,3,7);
INSERT_ELEMENTS(coll1,2,6);
INSERT_ELEMENTS(coll1,1,5);
PRINT_ELEMENTS(coll1);
// copy elements of coll1 sorted into coll6
vector<int>::iterator pos6;
pos6 = partial_sort_copy (coll1.begin(), coll1.end(),
coll6.begin(), coll6.end());
// print all copied elements
copy (coll6.begin(), pos6,ostream_iterator<int>(cout," "));
cout << endl;
}
/*
3 4 5 6 7 2 3 4 5 6 1 2 3 4 5
1 2 2 3 3 3
*/
Use partial_sort_copy with custom comparison function to copy elements in one container sorted into another container
/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
}
/* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
}
using namespace std;
int main()
{
deque<int> coll1;
vector<int> coll6(6); // initialize with 6 elements
vector<int> coll30(30); // initialize with 30 elements
INSERT_ELEMENTS(coll1,3,7);
INSERT_ELEMENTS(coll1,2,6);
INSERT_ELEMENTS(coll1,1,5);
PRINT_ELEMENTS(coll1);
// copy elements of coll1 sorted into coll30
vector<int>::iterator pos30;
pos30 = partial_sort_copy (coll1.begin(), coll1.end(),
coll30.begin(), coll30.end(),
greater<int>());
// print all copied elements
copy (coll30.begin(), pos30,
ostream_iterator<int>(cout," "));
cout << endl;
}
/*
3 4 5 6 7 2 3 4 5 6 1 2 3 4 5
7 6 6 5 5 5 4 4 4 3 3 3 2 2 1
*/