Python/project_euler/problem_07/sol1.py
Dhruv 719c5562d9
Add default args and type hints for problem 7 (#2973)
- Add default argument values
- Add type hints
- Change one letter variable names to a more descriptive one
- Add doctest for `solution()`
2020-10-08 07:57:47 +02:00

60 lines
1.1 KiB
Python

"""
Problem 7: https://projecteuler.net/problem=7
By listing the first six prime numbers:
2, 3, 5, 7, 11, and 13
We can see that the 6th prime is 13. What is the Nth prime number?
"""
from math import sqrt
def is_prime(num: int) -> bool:
"""Determines whether the given number is prime or not"""
if num == 2:
return True
elif num % 2 == 0:
return False
else:
sq = int(sqrt(num)) + 1
for i in range(3, sq, 2):
if num % i == 0:
return False
return True
def solution(nth: int = 10001) -> int:
"""Returns the n-th prime number.
>>> solution(6)
13
>>> solution(1)
2
>>> solution(3)
5
>>> solution(20)
71
>>> solution(50)
229
>>> solution(100)
541
>>> solution()
104743
"""
count = 0
number = 1
while count != nth and number < 3:
number += 1
if is_prime(number):
count += 1
while count != nth:
number += 2
if is_prime(number):
count += 1
return number
if __name__ == "__main__":
print(solution(int(input().strip())))