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Сombinatorics solution in Uncategorized category for Mathematically Lucky Tickets by bryukh
from itertools import combinations, product, permutations
from operator import add, sub, mul, truediv
from math import isnan
UNLUCKY = 100
OPERATORS = [add, sub, mul, truediv]
def check_separated(variant):
numbers = [int(v) for v in variant]
oper_length = len(variant) - 1
for oper_var in product(OPERATORS, repeat=oper_length):
for order in permutations(range(len(oper_var))):
temp = numbers[:]
num = 0
for i in order:
op = oper_var[i]
left = i
while isnan(temp[left]):
left -= 1
right = i + 1
while isnan(temp[right]):
right += 1
try:
num = op(temp[left], temp[right])
except ZeroDivisionError:
continue
temp[left] = num
temp[right] = float("NaN")
if round(num, 6) == UNLUCKY:
return False
return True
def split_ticket(s_str, dividers):
"""str, list[int] -> list[str]
Split string by dividers index
"""
res = []
start = 0
dividers = list(dividers) + [len(s_str)]
for d in dividers:
fragment = s_str[start:d]
if fragment:
res.append(fragment)
start = d
return res
def checkio(ticket):
#degenerated case
if int(ticket) == UNLUCKY:
return False
l_ticket = len(ticket)
for i in range(1, l_ticket):
for var in combinations(range(1, l_ticket), i):
separated = split_ticket(ticket, var)
if not check_separated(separated):
return False
#replace this for solution
return True
May 30, 2013
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