def c(n,m,out):
if(m==0):
return 1
x=n
while x>=m:
out.append(x)
if(c(x-1,m-1,out)):
print out
out.pop()
x-=1
return 0
c(10,8,out=[])
def permutation(listobj, length):
assert listobj != None and 0 < length <= len(listobj)
if(length == 1):
return [ [x] for x in listobj ]
result = []
for i in range(len(listobj)):
cp = list(listobj)
cur = cp[i]
del cp[i]
result.extend( [cur] + x for x in permutation(cp, length-1) )
return result
n个取m个数的组合数问题
