Implement Recursive Algorithms with Sub-workflows: Towers of Hanoi Demo

Description

How it works

This is an example of using sub-workflow nodes and a proof of concept showing that it’s possible to solve and explain recursive problems with n8n.

Towers of Hanoi - Task
Move a stack of n disks from rod A to rod C, using rod B as auxiliary. Only one disk can be moved at a time, and no disk may be placed on a smaller disk.

Example
n=4
| | |
= | |
=== | |
===== | |
======= | |
--------- --------- ---------
A B C
Algorithm
procedure Hanoi(n, X, Y, Z):
if n == 1:
move disk from X to Z
else:
Hanoi(n-1, X, Z, Y)
move disk from X to Z
Hanoi(n-1, Y, X, Z)

Notes
This is a learning example. In a real scenario, you would probably use an iterative approach with only a single code node.
When experimenting with recursion, make sure to define a termination condition first. Also, be aware of the "Restart workspace" link in the n8n Dashboard.
Learn more about Recursion on Wikipedia&oldid=1301600240#Towers_of_Hanoi).

Set up steps
Optional: Set "numberOfDiscs" in node "Set number of discs"
Execute workflow