From 354c70ccc683549b26a70bce0161f8b209f3fb19 Mon Sep 17 00:00:00 2001 From: Jack Kinsey Date: Wed, 4 Dec 2024 22:48:05 -0500 Subject: [PATCH] Tidy up day 4 --- src/day04.rs | 108 +++++++++++++++++++-------------------------------- 1 file changed, 41 insertions(+), 67 deletions(-) diff --git a/src/day04.rs b/src/day04.rs index 96e8f7b..1e47365 100644 --- a/src/day04.rs +++ b/src/day04.rs @@ -28,18 +28,13 @@ fn parse(input: &str) -> Vec> { .collect() } -fn find_chars(chars: &[Vec], char: Char) -> Vec<(i32, i32)> { - chars - .iter() - .enumerate() - .flat_map(|(i, v)| { - v.iter() - .enumerate() - .filter(|(_, &c)| c == char) - .map(move |(j, _)| (i, j)) - .map(|(i, j)| (i.try_into().unwrap(), j.try_into().unwrap())) - }) - .collect() +fn find_chars(chars: &[Vec], char: Char) -> impl Iterator + use<'_> { + chars.iter().zip(0..).flat_map(move |(v, i)| { + v.iter() + .zip(0..) + .filter(move |(&c, _)| c == char) + .map(move |(_, j)| (i, j)) + }) } #[rustfmt::skip] @@ -49,60 +44,47 @@ const DIRS: [(i32, i32); 8] = [ (1, -1), (1, 0), (1, 1), ]; -fn make_dirs((i, j): (i32, i32), n: i32) -> Vec<[(usize, usize); 4]> { +fn make_dirs<'a>( + (i, j): (i32, i32), + n: i32, +) -> impl Iterator + use<'a> { DIRS.iter() - .map(|dir| { + .map(move |dir| { [dir] .iter() .cycle() .take(4) - .enumerate() - .map(|(k, dij)| (std::convert::TryInto::::try_into(k).unwrap(), dij)) - .map(|(k, (di, dj))| (i + k * di, j + k * dj)) + .zip(0..) // to avoid type issues + .map(|((di, dj), k)| (i + k * di, j + k * dj)) .collect::>() - .try_into() - .unwrap() }) - .filter(|ds: &[(i32, i32); 4]| { + .filter(move |ds| { ds.iter() - .all(|(ii, jj)| *ii >= 0 && *jj >= 0 && *ii < n && *jj < n) + .all(|&(ii, jj)| ii >= 0 && jj >= 0 && ii < n && jj < n) }) - .map(|ds: [(i32, i32); 4]| { + .map(|ds| { ds.iter() - .map(|(ii, jj)| { - ( - TryInto::::try_into(*ii).unwrap(), - TryInto::::try_into(*jj).unwrap(), - ) - }) + .map(|&(ii, jj)| (ii.try_into().unwrap(), jj.try_into().unwrap())) .collect::>() .try_into() .unwrap() }) - .collect() } #[rustfmt::skip] const XDIRS: [(i32, i32); 4] = [ - (-1, -1), (-1, 1), - /* ctr */ - (1, -1), (1, 1), + (-1, -1), (-1, 1), + (1, -1), (1, 1), ]; fn make_xdirs((i, j): (i32, i32), n: i32) -> Option<[(usize, usize); 4]> { - if i == 0 || i == n - 1 || j == 0 || j == n - 1 { + if i == 0 || i >= n - 1 || j == 0 || j >= n - 1 { None } else { Some( XDIRS .iter() - .map(|&(di, dj)| (i + di, j + dj)) - .map(|(ii, jj)| { - ( - TryInto::::try_into(ii).unwrap(), - TryInto::::try_into(jj).unwrap(), - ) - }) + .map(|&(di, dj)| ((i + di).try_into().unwrap(), (j + dj).try_into().unwrap())) .collect::>() .try_into() .unwrap(), @@ -112,21 +94,18 @@ fn make_xdirs((i, j): (i32, i32), n: i32) -> Option<[(usize, usize); 4]> { fn check_x_for_xmas(chars: &[Vec], coords: (i32, i32)) -> usize { make_dirs(coords, chars.len().try_into().unwrap()) - .iter() - .map(|ijs| { + .filter(|ijs| { matches!( - ijs.iter().map(|(i, j)| chars[*i][*j]).collect::>()[..], + ijs.iter().map(|&(i, j)| chars[i][j]).collect::>()[..], [Char::X, Char::M, Char::A, Char::S] ) }) - .filter(|&x| x) .count() } fn check_xs_for_xmas(chars: &[Vec]) -> usize { find_chars(chars, Char::X) - .iter() - .map(|&coords| check_x_for_xmas(chars, coords)) + .map(|coords| check_x_for_xmas(chars, coords)) .sum() } @@ -138,23 +117,18 @@ const XPATTERNS: [[Char; 4]; 4] = [ ]; fn check_a_for_xmas(chars: &[Vec], coords: (i32, i32)) -> usize { - if let Some(x) = make_xdirs(coords, chars.len().try_into().unwrap()) { - let xc: [Char; 4] = x - .iter() - .map(|(i, j): &(usize, usize)| chars[*i][*j]) - .collect::>() - .try_into() - .unwrap(); - XPATTERNS.iter().filter(|&&p| p == xc).count() - } else { - 0 + match make_xdirs(coords, chars.len().try_into().unwrap()) { + Some(x) => { + let cs = &x.iter().map(|&(i, j)| chars[i][j]).collect::>()[..]; + XPATTERNS.iter().filter(|&p| p == cs).count() + } + None => 0, } } fn check_as_for_xmas(chars: &[Vec]) -> usize { find_chars(chars, Char::A) - .iter() - .map(|&coords| check_a_for_xmas(chars, coords)) + .map(|coords| check_a_for_xmas(chars, coords)) .sum() } @@ -200,8 +174,8 @@ mod test { [ Char::S, Char::M, Char::S, Char::M, Char::S, Char::A, Char::S, Char::X, Char::S, Char::S ], [ Char::S, Char::A, Char::X, Char::A, Char::M, Char::A, Char::S, Char::A, Char::A, Char::A ], [ Char::M, Char::A, Char::M, Char::M, Char::M, Char::X, Char::M, Char::M, Char::M, Char::M ], - [ Char::M, Char::X, Char::M, Char::X, Char::A, Char::X, Char::M, Char::A, Char::S, Char::X ] - ] + [ Char::M, Char::X, Char::M, Char::X, Char::A, Char::X, Char::M, Char::A, Char::S, Char::X ], + ], ) } @@ -209,7 +183,7 @@ mod test { #[test] fn test_find_xs() { assert_eq!( - find_chars(&parse(INPUT_STR), Char::X), + find_chars(&parse(INPUT_STR), Char::X).collect::>(), [ (0, 4), (0, 5), (1, 4), @@ -220,22 +194,22 @@ mod test { (6, 7), (7, 2), (8, 5), - (9, 1), (9, 3), (9, 5), (9, 9) - ] + (9, 1), (9, 3), (9, 5), (9, 9), + ], ) } #[test] fn test_make_dirs() { assert_eq!( - make_dirs((0, 4), 10), + make_dirs((0, 4), 10).collect::>(), [ [(0, 4), (0, 3), (0, 2), (0, 1)], [(0, 4), (0, 5), (0, 6), (0, 7)], [(0, 4), (1, 3), (2, 2), (3, 1)], [(0, 4), (1, 4), (2, 4), (3, 4)], - [(0, 4), (1, 5), (2, 6), (3, 7)] - ] + [(0, 4), (1, 5), (2, 6), (3, 7)], + ], ) } @@ -249,7 +223,7 @@ mod test { assert_eq!(make_xdirs((0, 4), 10), None); assert_eq!( make_xdirs((1, 1), 10), - Some([(0, 0), (0, 2), (2, 0), (2, 2)]) + Some([(0, 0), (0, 2), (2, 0), (2, 2)]), ); } -- 2.38.5