Fix style of the first ten solutions for Project Euler (#3242)

* Fix style of the first ten solutions for Project Euler

- Unify the header docstring, and add reference URLs to wikipedia
  or similar
- Fix docstrings to be properly multilined
- Add newlines where appropriate
- Add doctests where they were missing
- Remove doctests that test for the correct solution
- fix obvious spelling or grammar mistakes in comments and
  exception messages
- Fix line endings to be UNIX. This makes two of the files seem
  to have changed completely
- no functional changes in any of the solutions were done
  (except for the spelling fixes mentioned above)

* Fix docstrings and main function as per Style Guide

project_euler/problem_010/sol1.py

@@ -1,16 +1,23 @@
 """
-https://projecteuler.net/problem=10
+Project Euler Problem 10: https://projecteuler.net/problem=10
+
+Summation of primes
 
-Problem Statement:
 The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
 
 Find the sum of all the primes below two million.
+
+References:
+    - https://en.wikipedia.org/wiki/Prime_number
 """
+
 from math import sqrt
 
 
 def is_prime(n: int) -> bool:
-    """Returns boolean representing primality of given number num.
+    """
+    Returns boolean representing primality of given number num.
+
     >>> is_prime(2)
     True
     >>> is_prime(3)
@@ -20,6 +27,7 @@ def is_prime(n: int) -> bool:
     >>> is_prime(2999)
     True
     """
+
     for i in range(2, int(sqrt(n)) + 1):
         if n % i == 0:
             return False
@@ -28,11 +36,9 @@ def is_prime(n: int) -> bool:
 
 
 def solution(n: int = 2000000) -> int:
-    """Returns the sum of all the primes below n.
+    """
+    Returns the sum of all the primes below n.
 
-    # The code below has been commented due to slow execution affecting Travis.
-    # >>> solution(2000000)
-    # 142913828922
     >>> solution(1000)
     76127
     >>> solution(5000)
@@ -42,6 +48,7 @@ def solution(n: int = 2000000) -> int:
     >>> solution(7)
     10
     """
+
     if n > 2:
         sum_of_primes = 2
     else:
@@ -55,4 +62,4 @@ def solution(n: int = 2000000) -> int:
 
 
 if __name__ == "__main__":
-    print(solution(int(input().strip())))
+    print(f"{solution() = }")

project_euler/problem_010/sol2.py

@@ -1,10 +1,14 @@
 """
-https://projecteuler.net/problem=10
+Project Euler Problem 10: https://projecteuler.net/problem=10
+
+Summation of primes
 
-Problem Statement:
 The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
 
 Find the sum of all the primes below two million.
+
+References:
+    - https://en.wikipedia.org/wiki/Prime_number
 """
 import math
 from itertools import takewhile
@@ -12,7 +16,9 @@ from typing import Iterator
 
 
 def is_prime(number: int) -> bool:
-    """Returns boolean representing primality of given number num.
+    """
+    Returns boolean representing primality of given number num.
+
     >>> is_prime(2)
     True
     >>> is_prime(3)
@@ -22,12 +28,17 @@ def is_prime(number: int) -> bool:
     >>> is_prime(2999)
     True
     """
+
     if number % 2 == 0 and number > 2:
         return False
     return all(number % i for i in range(3, int(math.sqrt(number)) + 1, 2))
 
 
 def prime_generator() -> Iterator[int]:
+    """
+    Generate a list sequence of prime numbers
+    """
+
     num = 2
     while True:
         if is_prime(num):
@@ -36,11 +47,9 @@ def prime_generator() -> Iterator[int]:
 
 
 def solution(n: int = 2000000) -> int:
-    """Returns the sum of all the primes below n.
+    """
+    Returns the sum of all the primes below n.
 
-    # The code below has been commented due to slow execution affecting Travis.
-    # >>> solution(2000000)
-    # 142913828922
     >>> solution(1000)
     76127
     >>> solution(5000)
@@ -50,8 +59,9 @@ def solution(n: int = 2000000) -> int:
     >>> solution(7)
     10
     """
+
     return sum(takewhile(lambda x: x < n, prime_generator()))
 
 
 if __name__ == "__main__":
-    print(solution(int(input().strip())))
+    print(f"{solution() = }")

project_euler/problem_010/sol3.py

@@ -1,43 +1,47 @@
 """
-https://projecteuler.net/problem=10
+Project Euler Problem 10: https://projecteuler.net/problem=10
+
+Summation of primes
 
-Problem Statement:
 The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
 
 Find the sum of all the primes below two million.
+
+References:
+    - https://en.wikipedia.org/wiki/Prime_number
+    - https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
 """
 
 
 def solution(n: int = 2000000) -> int:
-    """Returns the sum of all the primes below n using Sieve of Eratosthenes:
+    """
+    Returns the sum of all the primes below n using Sieve of Eratosthenes:
 
-    https://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
     The sieve of Eratosthenes is one of the most efficient ways to find all primes
     smaller than n when n is smaller than 10 million.  Only for positive numbers.
 
-    >>> solution(2_000_000)
-    142913828922
-    >>> solution(1_000)
+    >>> solution(1000)
     76127
-    >>> solution(5_000)
+    >>> solution(5000)
     1548136
-    >>> solution(10_000)
+    >>> solution(10000)
     5736396
     >>> solution(7)
     10
-    >>> solution(7.1)  # doctest: +ELLIPSIS
+    >>> solution(7.1)  # doctest: +ELLIPSIS
     Traceback (most recent call last):
     ...
     TypeError: 'float' object cannot be interpreted as an integer
-    >>> solution(-7)  # doctest: +ELLIPSIS
+    >>> solution(-7)  # doctest: +ELLIPSIS
     Traceback (most recent call last):
     ...
     IndexError: list assignment index out of range
-    >>> solution("seven")  # doctest: +ELLIPSIS
+    >>> solution("seven")  # doctest: +ELLIPSIS
     Traceback (most recent call last):
     ...
     TypeError: can only concatenate str (not "int") to str
     """
+
     primality_list = [0 for i in range(n + 1)]
     primality_list[0] = 1
     primality_list[1] = 1
@@ -54,4 +58,4 @@ def solution(n: int = 2000000) -> int:
 
 
 if __name__ == "__main__":
-    print(solution(int(input().strip())))
+    print(f"{solution() = }")