ぶどうの房のパズル http://www2.oninet.ne.jp/mazra/math104.htm

puzzle_of_vine.py

# Python 2.7.5
#
# Usage:
#   $ python puzzle_of_vine.py STEP_NUMBER

import sys
import math

argv = sys.argv
if len(argv) < 2: exit("Error")
if not argv[1].isdigit(): exit("Error")
if argv[1] == "0": exit()

def triangle_number(number):
    return number * (number + 1) / 2

def sort_digits(steps, digits, step, grapes):
    if len(digits) < 1:
        print_vine(steps, grapes)
        return

    if triangle_number(step) == len(grapes):
        step = step + 1

    for i in digits:
        if 1 < step and triangle_number(step - 1) < len(grapes):
            if math.fabs(i - grapes[-1]) != grapes[-1 * step]:
                continue

        listed_grapes = list(grapes)
        listed_grapes.append(i)
        free_digits = list(digits)
        free_digits.remove(i)
        sort_digits(steps, free_digits, step, listed_grapes)

def print_vine(steps, grapes):
    for i in range(steps, 0, -1):
        print "".rjust(steps - i, " ") + " ".join(map(str, grapes[-1 * i:]))
        del grapes[-1 * i:]

    print "\n"


steps = int(argv[1])
digits = list(range(1, triangle_number(steps) + 1))

sort_digits(steps, digits, 1, [])