BOJ15650 N과 M 2

import sys
sys.setrecursionlimit(10**6)

N, M = map(int, input().split())

## 1 based
check = [False] * (N+1)
elem = [0] * M
def recur(idx, cnt):
	if cnt == M:
		for i in range(M):	
			print(elem[i], end=' ')
		print()
		return

	if idx > N:
		return
	
	elem[cnt] = idx
	recur(idx+1, cnt+1)
	elem[cnt] = 0
	recur(idx+1, cnt)

recur(1, 0)