STL算法-15局部排序

局部排序

1. partial_sort(b, se, e)

2. partial_sort(b, se, e, p)

3. partial_sort_copy(sb, se, db, de)

   1. 源區間

      [sb, se)

      ，目标區間

      [db, de)

   2. 傳回值：複制後的元素的下一個位置

4. partial_sort_copy(sb, se, db, de, p)

5. 預設從小到大升序排序。

partial_sort()

代碼示例

#include <iostream>
#include <deque>
#include <algorithm>
#include <functional>

using namespace std;

int main()
{
	deque<int> ideq;
	for (int i = 3; i <= 7; ++i)
		ideq.push_back(i);
	for (int i = 2; i <= 6; ++i)
		ideq.push_back(i);
	for (int i = 1; i <= 5; ++i)
		ideq.push_back(i);

	cout << "ideq原始資料：" << endl;
	for (deque<int>::iterator iter = ideq.begin();
		iter != ideq.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	cout << "隻排序前5個資料：（從小到大）" << endl;
	partial_sort(ideq.begin(), ideq.begin() + 5, ideq.end());
	for (deque<int>::iterator iter = ideq.begin();
		iter != ideq.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	cout << "隻排序前5個資料：（從大到小）" << endl;
	partial_sort(ideq.begin(), ideq.begin() + 5, ideq.end(), greater<int>());
	for (deque<int>::iterator iter = ideq.begin();
		iter != ideq.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	return 0;
}
           

partial_sort_copy()

代碼示例

#include <iostream>
#include <vector>
#include <deque>
#include <algorithm>
#include <functional>
#include <iterator>

using namespace std;

int main()
{
	deque<int> ideq;
	vector<int> ivec6(6), ivec30(30);

	for (int i = 3; i <= 7; ++i)
		ideq.push_back(i);
	for (int i = 2; i <= 6; ++i)
		ideq.push_back(i);
	for (int i = 1; i <= 5; ++i)
		ideq.push_back(i);

	cout << "ideq原始資料：" << endl;
	for (deque<int>::iterator iter = ideq.begin();
		iter != ideq.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	// 将ideq全部資料排序并拷貝到vec6（空間不夠）,則隻複制6個
	vector<int>::iterator pos6;
	pos6 = partial_sort_copy(ideq.begin(), ideq.end(),
		ivec6.begin(), ivec6.end());

	copy(ivec6.begin(), ivec6.end(), ostream_iterator<int>(cout, " "));
	cout << endl;

	copy(ivec6.begin(), pos6, ostream_iterator<int>(cout, " "));
	cout << endl;

	// 将ideq全部資料排序并拷貝到vec30
	vector<int>::iterator pos;
	pos = partial_sort_copy(ideq.begin(), ideq.end(),
		ivec30.begin(), ivec30.end(), greater<int>());

	copy(ivec30.begin(), ivec30.end(), ostream_iterator<int>(cout, " "));
	cout << endl;

	copy(ivec30.begin(), pos, ostream_iterator<int>(cout, " "));
	cout << endl;
    
	return 0;
}