Walking in Circles — hard Python for AI problem | Incognition

Walking in Circles

10 pts · 10 coins

Python for AIHard

Walking in Circles

A walker starts on square (0, 0) of a grid that goes on forever. moves is a list of one-letter steps:

step	change to `(x, y)`
`"N"`	`y` goes up by 1
`"S"`	`y` goes down by 1
`"E"`	`x` goes up by 1
`"W"`	`x` goes down by 1

Task: write first_revisit(moves). Return the first square, as a tuple (x, y), that the walker stands on for the second time.

The start square counts as visited before the first step.
If the walker never returns to a square, return None.

Examples

moves = ["N", "E", "S", "W", "N"]

returns [0, 0]

moves = ["E", "E", "N"]

returns None

Hints

solution.py

1def first_revisit(moves):
2    # your code here
3    pass
4