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#!/usr/local/bin/python3
import sys, argparse
import math
from itertools import permutations
# Task 2: Largest of Three
# You are given an array of integers >= 0.
# Write a script to return the largest number formed by concatenating some of the given integers in any order which is also multiple of 3. Return -1 if none found.
# See https://theweeklychallenge.org/blog/perl-weekly-challenge-245/#TASK2 for more information on this challenge
def main(argv):
argParser = argparse.ArgumentParser()
argParser.add_argument("-n", "--nums", nargs='+', type=int, help="space seperated list of positive integers e.g. -n 10 30 4 5")
args = argParser.parse_args()
if args.nums:
nums = args.nums
print( largest(nums) )
else:
# Example 1
nums = [8, 1, 9]
print( largest(nums) )
#Output: 981
# Example 2
nums = [8, 6, 7, 1, 0]
print( largest(nums) )
#Output: 8760
# Example 3
nums = [1]
print( largest(nums) )
#Output: -1
def largest(nums):
numbers_to_try = []
for i in range(len(nums)):
num_of_digits = i+1
perms = list(permutations(nums, num_of_digits))
for group_of_digits in perms:
combined_digits = int("".join(map(str, group_of_digits)))
numbers_to_try.append(combined_digits)
numbers_to_try.sort(reverse=True)
for num2try in numbers_to_try:
if num2try % 3 == 0:
return num2try
return -1
# # Use array of potential numbers in numerical descending sort order
# # to determine if any are divisible by 3
# foreach my $num_2_try (sort { $b <=> $a } @numbers_to_try) {
# # return the first (biggest) number found
# return $num_2_try unless $num_2_try % 3;
# }
# return -1 #default return value of -1 if no number found
if __name__ == "__main__":
main(sys.argv[1:])
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