美团笔试
a了4.25约面了
第四题dfs+剪枝只过了25%，咋做啊？
n,k = map(int,input().split())
l = list(map(int,input().split()))
res = []
path = []
def func(l):
l.sort()
for i in range(1,len(l)):
if l[i]%l[i-1]!=0:
return False
return True
def dfs(u):
if len(path[:])==n-k:
if func(path[:]):
res.append(path[:])
return
for i in range(u,n):
path.append(l[i])
dfs(i+1)
path.pop()
return res
ans = dfs(0)
print(len(ans)%(10**9+7))
