combNbyK (IA)

#include <bits/stdc++.h>
#define newline '\n'
#define ll long long
#define uns unsigned
#define deb(x) clog << x << ' '
#define debnewL(x) clog << x << newline
using namespace std;
///************************************
inline void __attribute__ ((constructor)) _cfun();
inline void _cfun()
{
    freopen("combinari.in", "r", stdin);
    freopen("combinari.out", "w", stdout);
    ios :: sync_with_stdio(NULL);
    cin.tie(nullptr);
    cout.tie(nullptr);
}
///************************************

int n, k;
int st[20];

inline void display()
{
    for (int i = 1; i <= k; i++)
        cout << st[i] << ' ';
    cout << newline;
}

void backtracking(int top)
{
    if (top == k + 1)
    {
        display();
        return;
    }

    for (int i = st[top - 1] + 1; i <= n; i++)
    {
        st[top] = i;
        backtracking(top + 1);
    }
}

signed main()
{
    cin >> n >> k;
    backtracking(1);
    return 0;
}