hanoi.py

hanoi.py

from collections import namedtuple



## Convention
##  4 3 2 1 size discs are stored as [ 4,3,2,1 ]
## name -> string
## discs -> sparse reverse sorted array of number 
Peg = namedtuple('Peg', ['name', 'discs'])



MOVES = 0

def mv( s , t, o ):
    """ move SINGLE disc """
    global MOVES
    d = s.discs.pop()
    if len(t.discs) > 0:
        assert d < t.discs[-1]
    t.discs.append(d)
    MOVES += 1
    print(f"MOVE({MOVES}): {d} from {s.name} ==> {t.name}")
    for z in sorted([s,t,o],key= lambda x : x.name):
        print(f"            {z}")

## [ 1 , 2, 3,4 ]
def hanoi(tomove, source, target, temp):
    if tomove < 0:
        return
    elif tomove == 1 :
        mv(source,target,temp)
    else:
        hanoi(tomove - 1 , source, temp, target)
        mv( source, target ,temp)
        hanoi(tomove - 1 , temp, target, source )

def main(n):
    a = Peg( 'A',  list(reversed(range(1, n + 1))))
    b = Peg( 'B',  [])
    c = Peg( 'C', [])
    hanoi(n, a,b,c)
    print("--- SOLVED ---")
    debug_dump(a,b,c)


def debug_dump(s, t, p):
    print("** SOURCE: ", s)
    print("** TARGET: ", t)
    print("** TEMP  : ", p)


main(10)