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@thisiswei
Last active December 18, 2015 22:28
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I feel I just got smarter
"""
The Towers of Hanoi is a puzzle where there is a pyramid of disks, each one
smaller than the one below it, all placed on to one of three rods. The puzzle
is to move all the disks from the left rod to the right rod, possibly using the
middle rod as necessary. You can only move one disk at a time, onto another
rod, but never moving a disk onto a disk that is smaller. Return a list of the
moves in the form[1, 'L', 'M'], which means to move disk number 1, the smallest
disk, from the left to the middle rod.
hanoi(2) → [[1, 'L', 'M'], [2, 'L', 'R'], [1, 'M', 'R']]
hanoi(1) → [[1, 'L', 'R']]
hanoi(0) → []
"""
#wtf! I figure this out! damn
def hanoi(n, start='L', end='R', using='M'):
if n <= 0:
return []
return (hanoi(n-1, start, using, end) +
[[n, start, end]] +
hanoi(n-1, using, end, start))
"""
Hint: You can break this down into pieces: to move a pile of n disks from rod L
to rod R, first move n-1 of them (all but the bottom disk) out of the way: to
rod M. Then move the bottom disk to rod R -- it will be clear because
everything is out of the way. Then, move the the pile of n-1 from M to B. Now,
how do you move the pile of n-1? The same way you moved the pile of n! It is
guaranteed to work, because whether you are moving n, n-1, n-2 or whatever,
they are all the smallest disks, and thus it doesn't matter where the other
disks are."""
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