递归......我被困住了

Question

The problem goes like :

Print a sequence of numbers starting with N, without using loop, in which

A[i+1] = A[i] - 5, if A[i]>0, else A[i+1]=A[i] + 5 repeat it until A[i]=N

So for input = 16 
output is 16 11 6 1 -4 1 6 11 16
input = 10 
output is 10 5 0 5 10

I am trying to analyse the solution how it is working once the number gets negative .

Here is the solution :

def print_pattern(n):
    print(n, end=' ')
    if n > 0:
        print_pattern(n - 5)
    else:
        return
    print(n, end=' ')

T = int(input())

for case in range(T):
    N = int(input())
print_pattern(N)
print()

Answer 1

As described, this appears to be an infinite recursion. For input = 16:

16 -> 11 # A[i+1] = A[i] - 5 (> 0)
11 -> 6  # A[i+1] = A[i] - 5 (> 0)
6 -> 1   # A[i+1] = A[i] - 5 (> 0)
1 -> -4  # A[i+1] = A[i] - 5 (> 0)
-4 -> 1  # A[i+1] = A[i] + 5 (<= 0)
1 -> -4  # A[i+1] = A[i] - 5 (> 0)
-4 -> 1  # A[i+1] = A[i] + 5 (<= 0)
etc.

so you'll never get an output of "16 11 6 1 -4 1 6 11 16" . Reread your problem and verify the rules.