순열과 조합

순열

#include <vector>
#include <iostream>
using namespace std;
int arr[5] = {1,2,3,4,5};
bool check[5];
vector<int> number;
int n,m; //nPm

void dfs(int depth)
{
	if(depth == m)
    {
    	for(int i=0;i<number.size();i++)
        {
        	cout << number[i] << ' ';
        }
        cout << endl;
        return;
    }
    for(int i=0;i<n;i++)
    {
    	if(check[i])continue;
        check[i] = true;
        number.push_back(arr[i]);
        dfs(depth+1);
        number.pop_back();
        check[i] = false;
    }
}

---

조합

#include <iostream>
#include <vector>
using namespace std;

int arr[5] = {1,2,3,4,5};
bool check[5];
int n,m;//nCm
void dfs(int depth, int idx)
{
	if(depth == m)
    {
    	for(int i=0;i<n;i++)
        {
        	if(check[i])
            {
            	cout << arr[i]<< ' ';
            }
        }
        cout << endl;
        return;
    }
    for(int i=idx;i<n;i++)
    {
    	if(check[i])continue;
        check[i] = true;
        dfs(depth+1, i);
        check[i] = false;
    }
}

---

중복순열

#include <iostream>
using namespace std;

int arr[5] = {1,2,3,4,5};
int arr2[5];
int n,m; 

void dfs(int depth)
{
	if(depth == m)
    {
    	for(int i=0;i<m;i++)
        {
        	cout << arr2[i]<< ' ';
        }
        cout << endl;
        return;
    }
    for(int i=0;i<n;i++)
    {
    	arr2[depth] = arr[i];
        dfs(depth+1);
    }
}

---

중복조합

#include <iostream>
#include <vector>
using namespace std;

int n,m;
int arr[5] = {1,2,3,4,5};
vector<int> v(5,0);

void dfs(int idx, int depth)
{
	if(depth == m)
    {
		for(int i=0;i<m;i++)
        {
        	cout << v[i] << ' ';
        }
        cout << endl;
        return;
	}
    for(int i=idx;i<n;i++)
    {
    	v[depth] = arr[i];
        dfs(i, depth+1);
    }
}