From 7d54056497eace210314454712d63a088da55180 Mon Sep 17 00:00:00 2001 From: Joan Date: Thu, 8 Oct 2020 10:27:07 +0200 Subject: [PATCH] [Project Euler] Fix code style in Problem 41 (#2992) * add problem title and link, fix f-string Signed-off-by: joan.rosellr * fix code style and improve doctests Signed-off-by: joan.rosellr * undo changes to the main call Signed-off-by: joan.rosellr * remove assignment operator in f-string Signed-off-by: joan.rosellr * add newline after first import to attempt to fix pre-commit workflow Signed-off-by: joan.rosellr * undo doctest changes, rename compute_pandigital_primes to solution Signed-off-by: joan.rosellr * update solution to return the actual solution instead of a list Signed-off-by: joan.rosellr * Update sol1.py Co-authored-by: Dhruv --- project_euler/problem_41/sol1.py | 42 +++++++++++++++++--------------- 1 file changed, 22 insertions(+), 20 deletions(-) diff --git a/project_euler/problem_41/sol1.py b/project_euler/problem_41/sol1.py index b4c0d842a..80ef2125b 100644 --- a/project_euler/problem_41/sol1.py +++ b/project_euler/problem_41/sol1.py @@ -1,20 +1,20 @@ +""" +Pandigital prime +Problem 41: https://projecteuler.net/problem=41 + +We shall say that an n-digit number is pandigital if it makes use of all the digits +1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime. +What is the largest n-digit pandigital prime that exists? + +All pandigital numbers except for 1, 4 ,7 pandigital numbers are divisible by 3. +So we will check only 7 digit pandigital numbers to obtain the largest possible +pandigital prime. +""" from __future__ import annotations from itertools import permutations from math import sqrt -""" -We shall say that an n-digit number is pandigital if it makes use of all the digits -1 to n exactly once. For example, 2143 is a 4-digit pandigital and is also prime. -What is the largest n-digit pandigital prime that exists? -""" - -""" -All pandigital numbers except for 1, 4 ,7 pandigital numbers are divisible by 3. -So we will check only 7 digit panddigital numbers to obtain the largest possible -pandigital prime. -""" - def is_prime(n: int) -> bool: """ @@ -35,20 +35,22 @@ def is_prime(n: int) -> bool: return True -def compute_pandigital_primes(n: int) -> list[int]: +def solution(n: int = 7) -> int: """ - Returns a list of all n-digit pandigital primes. - >>> compute_pandigital_primes(2) - [] - >>> max(compute_pandigital_primes(4)) + Returns the maximum pandigital prime number of length n. + If there are none, then it will return 0. + >>> solution(2) + 0 + >>> solution(4) 4231 - >>> max(compute_pandigital_primes(7)) + >>> solution(7) 7652413 """ pandigital_str = "".join(str(i) for i in range(1, n + 1)) perm_list = [int("".join(i)) for i in permutations(pandigital_str, n)] - return [num for num in perm_list if is_prime(num)] + pandigitals = [num for num in perm_list if is_prime(num)] + return max(pandigitals) if pandigitals else 0 if __name__ == "__main__": - print(f"{max(compute_pandigital_primes(7)) = }") + print(f"{solution() = }")