출처| https://www.acmicpc.net/problem/15650

코드

N,M = map(int, input().split())
rs = []

def recur(num):
    if len(rs) == M:
        print(' '.join(map(str,rs)))
        return
    
    for i in range(num,N+1):
        if i not in rs:
            rs.append(i)
            recur(i+1)
            rs.pop()
           
recur(1)