STL算法-12排列组合

排列组合

1. 排列组合前的数据必须先排序。
2. next_permutation()：原始数据为升序，从小到大排列
3. prev_permutation()：原始数据为降序，从大到小排列
4. 函数返回值为false：所有排列组合都已经排完

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
	vector<int> ivec;
	ivec.push_back(1);
	ivec.push_back(2);
	ivec.push_back(3);

	cout << "ivec原始数据：" << endl;
    for (vector<int>::iterator iter = ivec.begin();
		iter != ivec.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	/*next_permutation(ivec.begin(), ivec.end());
	for (vector<int>::iterator iter = ivec.begin();
		iter != ivec.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	next_permutation(ivec.begin(), ivec.end());
	for (vector<int>::iterator iter = ivec.begin();
		iter != ivec.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;*/

	cout << "ivec1排列组合数据：" << endl;
	while (next_permutation(ivec.begin(), ivec.end()))
	{
		for (vector<int>::iterator iter = ivec.begin();
			iter != ivec.end(); ++iter)
			cout << *iter << ' ';
		cout << endl;
	}
	cout << endl << endl;

	vector<int> ivec2;
	ivec2.push_back(3);
	ivec2.push_back(2);
	ivec2.push_back(1);

	cout << "ivec2原始数据：" << endl;
	for (vector<int>::iterator iter = ivec2.begin();
		iter != ivec2.end(); ++iter)
		cout << *iter << ' ';
	cout << endl;

	cout << "ivec2排列组合数据：" << endl;
	while (prev_permutation(ivec2.begin(), ivec2.end()))
	{
		for (vector<int>::iterator iter = ivec2.begin();
			iter != ivec2.end(); ++iter)
			cout << *iter << ' ';
		cout << endl;
	}
    
	return 0;
}