递归重复输出-Python 3

Question

I'm trying out recursion and am having trouble

Here's the code:

inputs = []
def ins(x,y,length):
    global inputs, j
    if [x,y] not in inputs:
        inputs.append([x,y])
    if x is not length:
        ins(x+1,y,length)
    if y is not length:
        ins(x,y+1,length)
j = 0
ins(0,0,12)

but it seems to go over the same x,y combo multiple times and gives an inputs ends up being 10400599 items long instead of just 169

Answer 1

my bad all i had to do was change:

if y is not length:

to:

elif y is not length: