Project Euler #7: 10001st prime

This article is part of a series where I'll be diving head first into the Project Euler puzzles. I want to document the challenge of solving such a puzzle and how I got to the answer. I want to prefix this by stating that I can't cheat for any of these challenges; with that I mean I can't look up any other implementations online. After the implementation, I will validate the answer by using this document or a similar sheet.

In this article I'll be solving: Project Euler #7.

Taking the is_prime() function from the “Largest prime factor”, we can solve this relatively easily:

fn problem_7() -> u64 {
    let mut start = 1;
    let mut index = 0;

    loop {
        start += 1;

        if is_prime(start) {
            index += 1
        }

        if index == 10001 {
            break start
        }
    }
}

#[test]
fn test_problem_7() {
    assert_eq!(problem_7(), 104743);
}

The full solution is available on GitHub.

63 62 61 60 59 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1