M	T	W	T	F	S	S
						1
2	3	4	5	6	7	8
9	10	11	12	13	14	15
16	17	18	18	20	21	22
23	24	25

[–] landreville 1 points 56 minutes ago

Rust

Blunt force grid navigation https://gitlab.com/landreville/advent-of-code-2024/-/blob/main/src/bin/04.rs

[–] [email protected] 2 points 2 hours ago

Rust

Ugh. Spent way too long on today's. Should have just used my own grid structure from last year. I will likely refactor to use that. Even though it's likely a super slow implementation, the convenience of dealing with it is better than shoehorning in the grid::Grid<T> from that crate.

solution (no supporting code)

use grid::Grid;

use crate::shared::{
    grid2d::{iter_diag_nesw, iter_diag_nwse, Point},
    util::read_lines,
};

fn parse_grid(input: &[String]) -> Grid<u8> {
    let cols = input.first().unwrap().len();
    Grid::from_vec(
        input
            .iter()
            .flat_map(|row| row.chars().map(|c| c as u8).collect::<Vec<u8>>())
            .collect(),
        cols,
    )
}

fn part1(grid: &Grid<u8>) -> usize {
    let mut xmas_count = 0;
    let rows = grid
        .iter_rows()
        .map(|d| String::from_utf8(d.copied().collect()).unwrap());
    let cols = grid
        .iter_cols()
        .map(|d| String::from_utf8(d.copied().collect()).unwrap());
    for diag in iter_diag_nesw(grid)
        .chain(iter_diag_nwse(grid))
        .filter_map(|d| {
            if d.len() >= 4 {
                Some(String::from_utf8(d.clone()).unwrap())
            } else {
                None
            }
        })
        .chain(rows)
        .chain(cols)
    {
        xmas_count += diag.matches("XMAS").count() + diag.matches("SAMX").count()
    }
    xmas_count
}

fn part2(grid: &Grid<u8>) -> usize {
    let mut xmas_count = 0;
    let valid = [
        [b'M', b'M', b'S', b'S'],
        [b'M', b'S', b'S', b'M'],
        [b'S', b'M', b'M', b'S'],
        [b'S', b'S', b'M', b'M'],
    ];
    for x in 1..grid.cols() - 1 {
        for y in 1..grid.rows() - 1 {
            if grid.get(y, x) == Some(&b'A')
                && valid.contains(
                    &(Point::new(x as isize, y as isize)
                        .diagonal_neighbors(grid)
                        .map(|i| i.unwrap_or(0))),
                )
            {
                xmas_count += 1;
            }
        }
    }
    xmas_count
}

pub fn solve() {
    let input = read_lines("inputs/day04.txt");
    let grid = parse_grid(&input);
    println!("Part 1: {}", part1(&grid));
    println!("Part 2: {}", part2(&grid));
}

And here's a link to the Github if you care to see the gross supporting code :D

[–] zarlin 2 points 5 hours ago

Nim

import ../aoc, strutils

type
  Cell* = tuple[x,y:int]

#the 8 grid direction
const directions : array[8, Cell] = [
  (1, 0), (-1, 0),
  (0, 1), ( 0,-1),
  (1, 1), (-1,-1),
  (1,-1), (-1, 1)
]

const xmas = "XMAS"

#part 1
proc searchXMAS*(grid:seq[string], x,y:int):int =
  #search in all 8 directions (provided we can find a full match in that direction)
  let w = grid[0].len
  let h = grid.len
  
  for dir in directions:
    # check if XMAS can even fit
    let xEnd = x + dir.x * 3
    let yEnd = y + dir.y * 3
    if xEnd < 0 or xEnd >= w or
       yEnd < 0 or yEnd >= h:
      continue;
    
    #step along direction
    var matches = 0
    for s in 0..3:
      if grid[y + dir.y * s][x + dir.x * s] == xmas[s]:
        inc matches
        
    if matches == xmas.len:
      inc result

#part 2
proc isMAS(grid:seq[string], c, o:Cell):bool=
  let ca : Cell = (c.x+o.x, c.y+o.y)
  let cb : Cell = (c.x-o.x, c.y-o.y)
  let a = grid[ca.y][ca.x]
  let b = grid[cb.y][cb.x]
  (a == 'M' and b == 'S') or (a == 'S' and b == 'M')

proc searchCrossMAS*(grid:seq[string], x,y:int):bool =
  grid[y][x] == 'A' and
  grid.isMAS((x,y), (1,1)) and
  grid.isMAS((x,y), (1,-1))

proc solve*(input:string): array[2,int] =
  let grid = input.splitLines
  let w = grid[0].len
  let h = grid.len
  
  #part 1
  for y in 0..<h:
    for x in 0..<w:
      result[0] += grid.searchXMAS(x, y)
  
  #part 2, skipping borders
  for y in 1..<h-1:
    for x in 1..<w-1:
      result[1] += (int)grid.searchCrossMAS(x, y)

Part 1 was done really quickly. Part 2 as well, but the result was not accepted...

Turns out +MAS isn't actually a thing :P

[–] Karmmah 1 points 4 hours ago* (last edited 4 hours ago)

Julia

Had some time to clean up the code today since the solution was quite straight forward after making a plan on how to approach it.

spoiler

function readWordSearch(inputFile::String)::Matrix{Char}
	f = open(inputFile,"r")
	lines::Vector{String} = readlines(f)
	close(f)
	wordSearch = Matrix{Char}(undef,length(lines),length(lines))
	for (i,line) in enumerate(lines)
		wordSearch[i,:] = collect(line)
	end
	return wordSearch
end

function countXMASAppearances(wS::Matrix{Char})::Int
	appearanceCount::Int = 0
	for i=1 : size(wS)[1] #lines
		for j=1 : size(wS)[2] #columns
			wS[i,j]!='X' ? continue : nothing #continue if char is not X
			#if char is X, check surrounding area
			# check horizontals
			#left
			j>=4 ? (wS[i,j-1]*wS[i,j-2]*wS[i,j-3]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			#right
			j<=size(wS)[2]-3 ? (wS[i,j+1]*wS[i,j+2]*wS[i,j+3]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			# check verticals
			#up
			i>=4 ? (wS[i-1,j]*wS[i-2,j]*wS[i-3,j]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			#down
			i<=size(wS)[1]-3 ? (wS[i+1,j]*wS[i+2,j]*wS[i+3,j]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			# check diagonals
			#left up
			i>=4 && j>=4 ? (wS[i-1,j-1]*wS[i-2,j-2]*wS[i-3,j-3]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			#right up
			i>=4 && j<=size(wS)[2]-3 ? (wS[i-1,j+1]*wS[i-2,j+2]*wS[i-3,j+3]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			#left down
			i<=size(wS)[1]-3 && j>=4 ? (wS[i+1,j-1]*wS[i+2,j-2]*wS[i+3,j-3]=="MAS" ? appearanceCount+=1 : nothing) : nothing
			#right down
			i<=size(wS)[1]-3 && j<=size(wS)[2]-3 ? (wS[i+1,j+1]*wS[i+2,j+2]*wS[i+3,j+3]=="MAS" ? appearanceCount+=1 : nothing) : nothing
		end
	end
	return appearanceCount
end

function countX_MASAppearances(wordSearch::Matrix{Char})::Int
	appearances::Int = 0
	for l=2 : size(wordSearch)[1]-1
		for c=2 : size(wordSearch)[2]-1
			wordSearch[l,c]!='A' ? continue : nothing
			checkArr = [wordSearch[l-1,c-1],wordSearch[l-1,c+1],wordSearch[l+1,c-1],wordSearch[l+1,c+1]]
			if checkArr in [['M','M','S','S'],['M','S','M','S'],['S','S','M','M'],['S','M','S','M']]
				appearances += 1
			end
		end
	end
	return appearances
end

wordSearch::Matrix{Char} = readWordSearch(inputFile
prinltn("part 1 appearances: $(countXMASAppearances(wordSearch))")
prinltn("part 2 appearances: $(countX_MASAppearances(wordSearch))")

[–] [email protected] 1 points 5 hours ago

Python

def read_input(path):
    with open(path) as f:
        lines = f.readlines()
        for i, line in enumerate(lines):
            ln = line.replace("\n","")
            lines[i] = ln
    return lines

def find_X(lines):
    Xes = []
    for j, line in enumerate(lines):
        ind = [i for i, ltr in enumerate(line) if ltr == "X"]
        for i in ind:
            Xes.append((j,i))
    return Xes

def find_M(lines, x, dim):
    # Check for Ms
    M_dirs = []
    for i in [-1, 0, 1]:
        x_ind = x[0] + i
        if x_ind>=0 and x_ind<dim:
            for j in [-1, 0, 1]:
                y_ind = x[1]+j
                if y_ind>=0 and y_ind<dim:
                    if lines[x_ind][y_ind] == "M":
                        M = [(x_ind, y_ind), (i,j)]
                        M_dirs.append(M)
    return M_dirs

def check_surroundings(loc, lines, check_char, direction):
    max = len(lines)-1
    check_lock = [loc[i]+direction[i] for i in range(len(loc))]
    if all(i>=0 and i<=max for i in check_lock) and check_char in str(lines[check_lock[0]][check_lock[1]]):
        return True
    else:
        return False

def part_one(lines):
    ans = 0 

    X = find_X(lines)
    dim = len(lines[0])
    for x in X:
        M = find_M(lines, x, dim)
        for m in M:
            loc = m[0]
            dir = m[1]
            
            if not check_surroundings(loc, lines, 'A', dir):
                continue
            
            loc = [loc[0]+dir[0], loc[1]+dir[1]]
            if not all(i>=0 and i<=dim-1 for i in loc):
                continue
            if not check_surroundings(loc, lines, 'S', dir):
                continue
            
            ans+=1
    return ans

def extract_square(lines, loc):
    str = ""
    for i in range(-1,2,1):
        for j in range(-1,2,1):
            x_ind = loc[0]+i
            y_ind = loc[1]+j
            if not all(p>=0 and p<=len(lines[0])-1 for p in [x_ind, y_ind]):
                raise ValueError("The given lock is at the edge of the grid and therefore will not produce a square")
            str += lines[x_ind][y_ind]
    return str

def check_square(square):
    if not square[4]=="A":
        return False
    elif not ((square[0]=="M" and square[8]=="S") or (square[0]=="S" and square[8]=="M")):
        return False
    elif not ((square[2]=="M" and square[6]=="S") or (square[2]=="S" and square[6]=="M")):
        return False
    else: return True

def part_two(lines):
    ans = 0
    dim = len(lines[0])
    for i in range(1,dim-1):
        for j in range(1,dim-1):
            square = extract_square(lines, (i,j))
            if check_square(square):
                ans += 1
    return ans

path = r'Day_4\input.txt'
lines = read_input(path)
print("Answer part 1: ", part_one(lines))
print("Answer part 2: ", part_two(lines))

[–] [email protected] 2 points 6 hours ago* (last edited 3 minutes ago)

Factor

spoiler

: get-input ( -- rows )
  "vocab:aoc-2024/04/input.txt" utf8 file-lines ;

: verticals ( rows -- lines )
  [ dimension last [0..b) ] keep cols ;

: slash-origins ( dimension -- coords )
  [ first [0..b) [ 0 2array ] map ] [
    first2 [ 1 - ] [ 1 (a..b] ] bi*
    [ 2array ] with map
  ] bi append ;

: backslash-origins ( dimension -- coords )
  first2
  [ [0..b) [ 0 2array ] map ]
  [ 1 (a..b] [ 0 swap 2array ] map ] bi* append ;

: slash ( rows origin -- line )
  first2
  [ 0 [a..b] ]
  [ pick dimension last [a..b) ] bi* zip
  swap matrix-nths ;

: backslash ( rows origin -- line )
  [ dup dimension ] dip first2
  [ over first [a..b) ]
  [ pick last [a..b) ] bi* zip nip
  swap matrix-nths ;

: slashes ( rows -- lines )
  dup dimension slash-origins
  [ slash ] with map ;

: backslashes ( rows -- lines )
  dup dimension backslash-origins
  [ backslash ] with map ;

: word-count ( line word -- n )
  dupd [ reverse ] dip
  '[ _ subseq-indices length ] bi@ + ;

: part1 ( -- n )
  get-input
  { [ ] [ verticals ] [ slashes ] [ backslashes ] } cleave-array concat
  [ "XMAS" word-count ] map-sum ;

: origin-adistances ( rows origins line-quot: ( rows origin -- line ) -- origin-adistances-assoc )
  with zip-with
  "MAS" "SAM" [ '[ [ _ subseq-indices ] map-values ] ] bi@ bi append
  harvest-values
  [ [ 1 + ] map ] map-values ; inline

: a-coords ( origin-adistances coord-quot: ( adistance -- row-delta col-delta ) -- coords )
  '[ first2 [ @ 2array v+ ] with map ] map-concat ; inline

: slash-a-coords ( rows -- coords )
  dup dimension slash-origins [ slash ] origin-adistances
  [ [ 0 swap - ] keep ] a-coords ;

: backslash-a-coords ( rows -- coords )
  dup dimension backslash-origins [ backslash ] origin-adistances
  [ dup ] a-coords ;

: part2 ( -- n )
  get-input [ slash-a-coords ] [ backslash-a-coords ] bi
  intersect length ;

Better viewed on GitHub.

[–] [email protected] 1 points 10 hours ago

This one was a little bit of a pain. I loved it.

TypeScript

Solution

import { AdventOfCodeSolutionFunction } from "./solutions";

enum Direction {
    UP,
    UP_RIGHT,
    RIGHT,
    BOTTOM_RIGHT,
    BOTTOM,
    BOTTOM_LEFT,
    LEFT,
    UP_LEFT,
};

const ALL_DIRECTIONS = [
    Direction.RIGHT,
    Direction.BOTTOM_RIGHT,
    Direction.BOTTOM,
    Direction.BOTTOM_LEFT,
    Direction.LEFT,
    Direction.UP_LEFT,
    Direction.UP,
    Direction.UP_RIGHT,
];

const check_coords = (grid: Array<Array<string>>, x: number, y: number) => {
    return y >= grid.length ||
        y < 0 ||
        x >= grid[y].length ||
        x < 0
}

const search_direction = (grid: Array<Array<string>>, x: number, y: number, direction: Direction, find: Array<string>) => {
    // exit conditions
    // no more to find
    if (find.length == 0)
        return 1; // found the end

    // invalid coords
    if (check_coords(grid, x, y))
        return 0;

    // make new mutable list
    const newFind = [...find];
    const searchChar = newFind.shift();

    // wrong character
    if (grid[y][x] !== searchChar)
        return 0;

    switch (direction) {
        case Direction.UP:
            return search_direction(grid, x, y + 1, direction, newFind);

        case Direction.UP_RIGHT:
            return search_direction(grid, x + 1, y + 1, direction, newFind);

        case Direction.RIGHT:
            return search_direction(grid, x + 1, y, direction, newFind);

        case Direction.BOTTOM_RIGHT:
            return search_direction(grid, x + 1, y - 1, direction, newFind);

        case Direction.BOTTOM:
            return search_direction(grid, x, y - 1, direction, newFind);

        case Direction.BOTTOM_LEFT:
            return search_direction(grid, x - 1, y - 1, direction, newFind);

        case Direction.LEFT:
            return search_direction(grid, x - 1, y, direction, newFind);

        case Direction.UP_LEFT:
            return search_direction(grid, x - 1, y + 1, direction, newFind);

        default:
            return 0;
    }
}

const part_1_search = (grid: Array<Array<string>>, x: number, y: number, find: Array<string>) => {
    return ALL_DIRECTIONS.reduce<number>(
        (instances, direction) =>
            instances + search_direction(grid, x, y, direction, find),
        0
    );
}

const part_2_search = (grid: Array<Array<string>>, x: number, y: number, find: Array<string>) => {
    return (
        search_direction(grid, x - 1, y + 1, Direction.BOTTOM_RIGHT, find) +
        search_direction(grid, x + 1, y + 1, Direction.BOTTOM_LEFT, find) +
        search_direction(grid, x - 1, y - 1, Direction.UP_RIGHT, find) +
        search_direction(grid, x + 1, y - 1, Direction.UP_LEFT, find)
    ) == 2 ? 1 : 0;
}

export const solution_4: AdventOfCodeSolutionFunction = (input) => {
    const grid = input.split("\n").map(st => st.trim()).map(v => v.split(""));

    let part_1 = 0;
    let part_2 = 0;

    const find_1 = "XMAS".split("");
    const find_2 = "MAS".split("");

    for (let y = 0; y < grid.length; y++) {
        for (let x = 0; x < grid[y].length; x++) {
            part_1 += part_1_search(grid, x, y, find_1);
            part_2 += part_2_search(grid, x, y, find_2);
        }
    }

    return {
        part_1,
        part_2,
    };
}

Felt like this code quality is better than what I usually output :)

[–] [email protected] 1 points 12 hours ago

Go

Just a bunch of ifs and bounds checking. Part 2 was actually simpler.

Code

func part1(W [][]rune) {
	m := len(W)
	n := len(W[0])
	xmasCount := 0

	for i := 0; i < m; i++ {
		for j := 0; j < n; j++ {
			if W[i][j] != 'X' {
				continue
			}
			if j < n-3 && W[i][j+1] == 'M' && W[i][j+2] == 'A' && W[i][j+3] == 'S' {
				// Horizontal left to right
				xmasCount++
			}
			if j >= 3 && W[i][j-1] == 'M' && W[i][j-2] == 'A' && W[i][j-3] == 'S' {
				// Horizontal right to left
				xmasCount++
			}
			if i < m-3 && W[i+1][j] == 'M' && W[i+2][j] == 'A' && W[i+3][j] == 'S' {
				// Vertical up to down
				xmasCount++
			}
			if i >= 3 && W[i-1][j] == 'M' && W[i-2][j] == 'A' && W[i-3][j] == 'S' {
				// Vertical down to up
				xmasCount++
			}
			if j < n-3 && i < m-3 && W[i+1][j+1] == 'M' && W[i+2][j+2] == 'A' && W[i+3][j+3] == 'S' {
				// Diagonal left to right and up to down
				xmasCount++
			}
			if j >= 3 && i < m-3 && W[i+1][j-1] == 'M' && W[i+2][j-2] == 'A' && W[i+3][j-3] == 'S' {
				// Diagonal right to left and up to down
				xmasCount++
			}
			if j < n-3 && i >= 3 && W[i-1][j+1] == 'M' && W[i-2][j+2] == 'A' && W[i-3][j+3] == 'S' {
				// Diagonal left to right and down to up
				xmasCount++
			}
			if j >= 3 && i >= 3 && W[i-1][j-1] == 'M' && W[i-2][j-2] == 'A' && W[i-3][j-3] == 'S' {
				// Diagonal right to left and down to up
				xmasCount++
			}
		}
	}

	fmt.Println(xmasCount)
}

func part2(W [][]rune) {
	m := len(W)
	n := len(W[0])
	xmasCount := 0

	for i := 0; i <= m-3; i++ {
		for j := 0; j <= n-3; j++ {
			if W[i+1][j+1] != 'A' {
				continue
			}
			if W[i][j] == 'M' && W[i][j+2] == 'M' && W[i+2][j] == 'S' && W[i+2][j+2] == 'S' {
				xmasCount++
			} else if W[i][j] == 'M' && W[i][j+2] == 'S' && W[i+2][j] == 'M' && W[i+2][j+2] == 'S' {
				xmasCount++
			} else if W[i][j] == 'S' && W[i][j+2] == 'S' && W[i+2][j] == 'M' && W[i+2][j+2] == 'M' {
				xmasCount++
			} else if W[i][j] == 'S' && W[i][j+2] == 'M' && W[i+2][j] == 'S' && W[i+2][j+2] == 'M' {
				xmasCount++
			}
		}
	}

	fmt.Println(xmasCount)
}

func main() {
	file, _ := os.Open("input.txt")
	defer file.Close()
	scanner := bufio.NewScanner(file)

	var W [][]rune
	for scanner.Scan() {
		line := scanner.Text()
		W = append(W, []rune(line))
	}

	part1(W)
	part2(W)
}

[–] vole 1 points 12 hours ago

Raku

Oof, my struggle to make custom index walking paths for part 1 did not pay off for part 2.

Solution

sub MAIN($input) {
    my $file = (open $input).slurp;
    my @grid is List = $file.lines».comb».list;
    my @transposedGrid is List = [Z] @grid;
    my @reversedGrid is List = @grid».reverse;
    my @transposedReversedGrid is List = @transposedGrid».reverse;

    my @horizontalScanRows is List = generateScanHorizontal(@grid);
    my @transposedHorizontalScanRows is List = generateScanHorizontal(@transposedGrid);

    my @part-one-counts = [];
    @part-one-counts.push(count-xmas(@grid, @horizontalScanRows)); # Right
    @part-one-counts.push(count-xmas(@transposedGrid, @transposedHorizontalScanRows)); # Down
    @part-one-counts.push(count-xmas(@reversedGrid, @horizontalScanRows)); # Left
    @part-one-counts.push(count-xmas(@transposedReversedGrid, @transposedHorizontalScanRows)); # Up

    my @diagonalScanRows is List = generateScanDiagonal(@grid);
    my @transposedDiagonalScanRows is List = generateScanDiagonal(@transposedGrid);
    @part-one-counts.push(count-xmas(@grid, @diagonalScanRows)); # Down Right
    @part-one-counts.push(count-xmas(@grid, @diagonalScanRows».reverse)); # Up Left
    @part-one-counts.push(count-xmas(@reversedGrid, @diagonalScanRows)); # Down Left
    @part-one-counts.push(count-xmas(@reversedGrid, @diagonalScanRows».reverse)); # Up Right

    my $part-one-solution = @part-one-counts.sum;
    say "part 1: $part-one-solution";


    my @part-two-counts = [];
    @part-two-counts.push(countGridMatches(@grid, (<M . S>,<. A .>,<M . S>)));
    @part-two-counts.push(countGridMatches(@grid, (<S . S>,<. A .>,<M . M>)));
    @part-two-counts.push(countGridMatches(@grid, (<S . M>,<. A .>,<S . M>)));
    @part-two-counts.push(countGridMatches(@grid, (<M . M>,<. A .>,<S . S>)));

    my $part-two-solution = @part-two-counts.sum;
    say "part 2: $part-two-solution";

}

sub count-xmas(@grid, @scanRows) {
    my $xmas-count = 0;
    for @scanRows -> @scanRow {
        my $xmas-pos = 0;
        for @scanRow -> @pos {
            my $char = @grid[@pos[0]][@pos[1]];
            if "X" eq $char {
                $xmas-pos = 1;
            }elsif <X M A S>[$xmas-pos] eq $char {
                if $xmas-pos == 3 {
                    $xmas-pos = 0;
                    $xmas-count += 1;
                } else {
                    $xmas-pos += 1;
                }
            } else {
                $xmas-pos = 0;
            }
        }
    }
    return $xmas-count;
}

sub generateScanHorizontal(@grid) {
    # Horizontal
    my $rows = @grid.elems;
    my $cols = @grid[0].elems;
    my @scanRows = ();
    for 0..^$rows -> $row {
        my @scanRow = ();
        for 0..^$cols -> $col {
            @scanRow.push(($row, $col));
        }
        @scanRows.push(@scanRow);
    }
    return @scanRows.List».List;
}

sub generateScanDiagonal(@grid) {
    # Down-right diagonal
    my $rows = @grid.elems;
    my $cols = @grid[0].elems;
    my @scanRows = ();
    for 0..^($rows + $cols - 1) -> $diag {
        my @scanRow = ();
        my $starting-row = max(-$cols + $diag + 1, 0);
        my $starting-col = max($rows - $diag - 1, 0);
        my $diag-len = min($rows - $starting-row, $cols - $starting-col);
        for 0..^$diag-len -> $diag-pos {
            @scanRow.push(($starting-row + $diag-pos, $starting-col + $diag-pos));
        }
        @scanRows.push(@scanRow);
    }
    return @scanRows.List».List;
}

sub countGridMatches(@grid, @needle) {
    my $count = 0;
    for 0..(@grid.elems - @needle.elems) -> $top {
        TOP-LEFT:
        for 0..(@grid[$top].elems - @needle[0].elems) -> $left {
            for 0..^@needle.elems -> $row-offset {
                for 0..^@needle[$row-offset].elems -> $col-offset {
                    my $needle-char = @needle[$row-offset][$col-offset];
                    next if $needle-char eq ".";
                    next TOP-LEFT if $needle-char ne @grid[$top+$row-offset][$left+$col-offset];
                }
            }
            $count += 1;
        }
    }
    return $count;
}

github

[–] [email protected] 1 points 13 hours ago

C#

namespace Day04;

static class Program
{
    public record struct Point(int Row, int Col);

    static void Main(string[] args)
    {
        var sample = File.ReadAllLines("sample.txt");
        var data = File.ReadAllLines("data.txt");

        Console.WriteLine($"Part 1 (sample): {SolvePart1(sample)}");
        Console.WriteLine($"Part 1 (data): {SolvePart1(data)}");

        Console.WriteLine($"Part 2 (sample): {SolvePart2(sample)}");
        Console.WriteLine($"Part 2 (data): {SolvePart2(data)}");
    }

    private static readonly string Search = "XMAS";

    private static readonly Func<Point, Point>[] DirectionalMoves =
    {
        p => new Point(p.Row + 1, p.Col),
        p => new Point(p.Row + 1, p.Col + 1),
        p => new Point(p.Row, p.Col + 1),
        p => new Point(p.Row - 1, p.Col + 1),
        p => new Point(p.Row - 1, p.Col),
        p => new Point(p.Row - 1, p.Col - 1),
        p => new Point(p.Row, p.Col - 1),
        p => new Point(p.Row + 1, p.Col - 1),
    };

    private static readonly Func<Point, Point>[] ForwardSlashMoves =
    {
        p => new Point(p.Row - 1, p.Col - 1),
        p => new Point(p.Row + 1, p.Col + 1),
    };
    
    private static readonly Func<Point, Point>[] BackSlashMoves =
    {
        p => new Point(p.Row + 1, p.Col - 1),
        p => new Point(p.Row - 1, p.Col + 1),
    };

    static long SolvePart1(string[] data)
    {
        return Enumerable
            .Range(0, data.Length)
            .SelectMany(row => Enumerable.Range(0, data[row].Length)
                .Select(col => new Point(row, col)))
            .Where(p => IsMatch(data, p, Search[0]))
            .Sum(p => DirectionalMoves
                .Count(move => DeepMatch(data, move(p), move, Search, 1)));
    }

    static long SolvePart2(string[] data)
    {
        return Enumerable
            .Range(0, data.Length)
            .SelectMany(row => Enumerable.Range(0, data[row].Length)
                .Select(col => new Point(row, col)))
            .Where(p => IsMatch(data, p, 'A'))
            .Count(p => CheckDiagonalMoves(data, p, ForwardSlashMoves)
                        && CheckDiagonalMoves(data, p, BackSlashMoves));
    }

    static bool CheckDiagonalMoves(string[] data, Point p, Func<Point, Point>[] moves)
        => (IsMatch(data, moves[0](p), 'S') && IsMatch(data, moves[1](p), 'M'))
           || (IsMatch(data, moves[0](p), 'M') && IsMatch(data, moves[1](p), 'S'));

    static bool DeepMatch(string[] data, Point p, Func<Point, Point> move, string search, int searchIndex) =>
        (searchIndex >= search.Length) ? true :
        (!IsMatch(data, p, search[searchIndex])) ? false :
        DeepMatch(data, move(p), move, search, searchIndex + 1);

    static bool IsMatch(string[] data, Point p, char searchChar)
        => IsInBounds(data, p) && (data[p.Row][p.Col] == searchChar);

    static bool IsInBounds(string[] data, Point p) =>
        (p.Row >= 0) && (p.Col >= 0) && (p.Row < data.Length) && (p.Col < data[0].Length);
}

[–] [email protected] 1 points 13 hours ago

Kotlin

fun part1(input: String): Int {
    return countWordOccurrences(input.lines())
}

fun part2(input: String): Int {
    val grid = input.lines().map(String::toList)
    var count = 0
    for (row in 1..grid.size - 2) {
        for (col in 1..grid[row].size - 2) {
            if (grid[row][col] == 'A') {
                count += countCrossMatch(grid, row, col)
            }
        }
    }
    return count
}

private fun countCrossMatch(grid: List<List<Char>>, row: Int, col: Int): Int {
    val surroundingCorners = listOf(
        grid[row - 1][col - 1], // upper left
        grid[row - 1][col + 1], // upper right
        grid[row + 1][col - 1], // lower left
        grid[row + 1][col + 1], // lower right
    )
    // no matches:
    //   M S   S M
    //    A     A
    //   S M   M S
    return if (surroundingCorners.count { it == 'M' } == 2
        && surroundingCorners.count { it == 'S' } == 2
        && surroundingCorners[0] != surroundingCorners[3]
    ) 1 else 0
}

private fun countWordOccurrences(matrix: List<String>): Int {
    val rows = matrix.size
    val cols = if (rows > 0) matrix[0].length else 0
    val directions = listOf(
        Pair(0, 1),   // Horizontal right
        Pair(1, 0),   // Vertical down
        Pair(1, 1),   // Diagonal down-right
        Pair(1, -1),  // Diagonal down-left
        Pair(0, -1),  // Horizontal left
        Pair(-1, 0),  // Vertical up
        Pair(-1, -1), // Diagonal up-left
        Pair(-1, 1)   // Diagonal up-right
    )

    fun isWordAt(row: Int, col: Int, word: String, direction: Pair<Int, Int>): Boolean {
        val (dx, dy) = direction
        for (i in word.indices) {
            val x = row + i * dx
            val y = col + i * dy
            if (x !in 0 until rows || y !in 0 until cols || matrix[x][y] != word[i]) {
                return false
            }
        }
        return true
    }

    var count = 0

    for (row in 0 until rows) {
        for (col in 0 until cols) {
            for (direction in directions) {
                if (isWordAt(row, col, "XMAS", direction)) {
                    count++
                }
            }
        }
    }

    return count
}

[–] mykl 2 points 17 hours ago* (last edited 11 hours ago) (1 children)

Uiua

Just part1 for now as I need to walk the dog :-)

[edit] Part 2 now added, and a nicer approach than Part 1 in my opinion, if you're able to keep that many dimensions straight in your head :-)

[edit 2] Tightened it up a bit more.

Grid ← ⊜∘⊸≠@\n "MMMSXXMASM\nMSAMXMSMSA\nAMXSXMAAMM\nMSAMASMSMX\nXMASAMXAMM\nXXAMMXXAMA\nSMSMSASXSS\nSAXAMASAAA\nMAMMMXMMMM\nMXMXAXMASX"

≡⍉⍉×⇡4¤[1_0 0_1 1_1 1_¯1]         # Use core dirs to build sets of 4-offsets.
↯∞_2⇡△ Grid                       # Get all possible starting points.
&p/+♭⊞(+∩(≍"XMAS")⇌.⬚@.⊡:Grid≡+¤) # Part 1. Join the two into a table, use to pick 4-elements, check, count.

Diags   ← [[¯. 1_1] [¯. 1_¯1]]
BothMas ← /×≡(+∩(≍"MS")⇌.)⬚@.⊡≡+Diags¤¤ # True if both diags here are MAS.
&p/+≡BothMas⊚="A"⟜¤Grid                 # Part 2. For all "A"s in grid, check diags, count where good.

[–] [email protected] 3 points 14 hours ago (1 children)

I'm not even sure how to write most of these characters

[–] mykl 2 points 12 hours ago (1 children)

The operators have all got ascii names you can type, and the formatter converts them to the symbols. It's a bit odd but really worthwhile, as you get access to the powerful array handling functionality that made solving today's challenges so much more straightforward than in other languages.

[–] [email protected] 2 points 9 hours ago

It looks quite functional indeed

[–] [email protected] 2 points 17 hours ago

C

What can I say, bunch of for loops! I add a 3 cell border to avoid having to do bounds checking in the inner loops.

Code

#include "common.h"
#define GZ 146

int main(int argc, char **argv) {
	static char g[GZ][GZ];
	static const char w[] = "XMAS";
	int p1=0,p2=0, x,y, m,i;

	if (argc > 1) DISCARD(freopen(argv[1], "r", stdin));
	for (y=3; y<GZ && fgets(g[y]+3, GZ-3, stdin); y++) ;

	for (y=3; y<GZ-3; y++)
	for (x=3; x<GZ-3; x++) {
		for (m=1,i=0; i<4; i++) {m &= g[y+i][x]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y-i][x]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y][x+i]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y][x-i]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y+i][x+i]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y-i][x-i]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y+i][x-i]==w[i];} p1+=m;
		for (m=1,i=0; i<4; i++) {m &= g[y-i][x+i]==w[i];} p1+=m;

		p2 += g[y+1][x+1]=='A' &&
		      ((g[y][x]  =='M' && g[y+2][x+2]=='S')  ||
		       (g[y][x]  =='S' && g[y+2][x+2]=='M')) &&
		      ((g[y+2][x]=='M' && g[y][x+2]  =='S')  ||
		       (g[y+2][x]=='S' && g[y][x+2]  =='M'));
	}

	printf("04: %d %d\n", p1, p2);
}

https://github.com/sjmulder/aoc/blob/master/2024/c/day04.c

[–] [email protected] 4 points 20 hours ago* (last edited 20 hours ago)

Nim

Could be done more elegantly, but I haven’t bothered yet.

proc solve(input: string): AOCSolution[int, int] =
  var lines = input.splitLines()

  block p1:
    # horiz
    for line in lines:
      for i in 0..line.high-3:
        if line[i..i+3] in ["XMAS", "SAMX"]:
          inc result.part1

    for y in 0..lines.high-3:
      #vert
      for x in 0..lines[0].high:
        let word = collect(for y in y..y+3: lines[y][x])
        if word in [@"XMAS", @"SAMX"]:
          inc result.part1

      #diag \
      for x in 0..lines[0].high-3:
        let word = collect(for d in 0..3: lines[y+d][x+d])
        if word in [@"XMAS", @"SAMX"]:
          inc result.part1

      #diag /
      for x in 3..lines[0].high:
        let word = collect(for d in 0..3: lines[y+d][x-d])
        if word in [@"XMAS", @"SAMX"]:
          inc result.part1

  block p2:
    for y in 0..lines.high-2:
      for x in 0..lines[0].high-2:
        let diagNW = collect(for d in 0..2: lines[y+d][x+d])
        let diagNE = collect(for d in 0..2: lines[y+d][x+2-d])
        if diagNW in [@"MAS", @"SAM"] and diagNE in [@"MAS", @"SAM"]:
          inc result.part2

Codeberg repo

[–] VegOwOtenks 4 points 21 hours ago

I struggled a lot more when doing list slices that I would've liked to

Haskell


import Data.List qualified as List

collectDiagonal :: [String] -> Int -> Int -> String
collectDiagonal c y x
        | length c > y && length (c !! y) > x = c !! y !! x : collectDiagonal c (y+1) (x+1)
        | otherwise = []

part1 c = do
        let forwardXMAS  = map (length . filter (List.isPrefixOf "XMAS") . List.tails) $ c
        let backwardXMAS = map (length . filter (List.isPrefixOf "XMAS") . List.tails . reverse) $ c
        let downwardXMAS  = map (length . filter (List.isPrefixOf "XMAS") . List.tails ) . List.transpose $ c
        let upwardXMAS = map (length . filter (List.isPrefixOf "XMAS") . List.tails . reverse ) . List.transpose $ c
        let leftSideDiagonals = map (\ y -> collectDiagonal c y 0) [0..length c]
        let leftTopDiagonals = map (\ x -> collectDiagonal c 0 x) [1..(length . List.head $ c)]
        let leftDiagonals = leftSideDiagonals ++ leftTopDiagonals
        let rightSideDiagonals = map (\ y -> collectDiagonal (map List.reverse c) y 0) [0..length c]
        let rightTopDiagonals = map (\ x -> collectDiagonal (map List.reverse c) 0 x) [1..(length . List.head $ c)]
        let rightDiagonals = rightSideDiagonals ++ rightTopDiagonals
        let diagonals = leftDiagonals ++ rightDiagonals

        let diagonalXMAS = map (length . filter (List.isPrefixOf "XMAS") . List.tails) $ diagonals
        let reverseDiagonalXMAS = map (length . filter (List.isPrefixOf "XMAS") . List.tails . reverse) $ diagonals

        print . sum $ [sum forwardXMAS, sum backwardXMAS, sum downwardXMAS, sum upwardXMAS, sum diagonalXMAS, sum reverseDiagonalXMAS]
        return ()

getBlock h w c y x = map (take w . drop x) . take h . drop y $ c

isXBlock b = do
        let diagonal1 = collectDiagonal b 0 0
        let diagonal2 = collectDiagonal (map List.reverse b) 0 0

        diagonal1 `elem` ["SAM", "MAS"] && diagonal2 `elem` ["SAM", "MAS"]

part2 c = do
        
        let lineBlocks = List.map (getBlock 3 3 c) [0..length c - 1]
        let groupedBlocks = List.map (flip List.map [0..(length . head $ c) - 1]) lineBlocks

        print . sum . map (length . filter isXBlock) $ groupedBlocks

        return ()

main = do
        c <- lines <$> getContents

        part1 c
        part2 c

        return ()

[–] TunaCowboy 2 points 18 hours ago* (last edited 17 hours ago)

python

solution

import aoc

def setup():
    return (aoc.get_lines(4, padded=(True, '.', 3)), 0)

def one():
    lines, acc = setup()
    for row, l in enumerate(lines):
        for col, c in enumerate(l):
            if c == 'X':
                w = l[col - 3:col + 1]
                e = l[col:col + 4]
                n = c + lines[row - 1][col] + \
                    lines[row - 2][col] + lines[row - 3][col]
                s = c + lines[row + 1][col] + \
                    lines[row + 2][col] + lines[row + 3][col]
                nw = c + lines[row - 1][col - 1] + \
                    lines[row - 2][col - 2] + lines[row - 3][col - 3]
                ne = c + lines[row - 1][col + 1] + \
                    lines[row - 2][col + 2] + lines[row - 3][col + 3]
                sw = c + lines[row + 1][col - 1] + \
                    lines[row + 2][col - 2] + lines[row + 3][col - 3]
                se = c + lines[row + 1][col + 1] + \
                    lines[row + 2][col + 2] + lines[row + 3][col + 3]
                for word in [w, e, n, s, nw, ne, sw, se]:
                    if word in ['XMAS', 'SAMX']:
                        acc += 1
    print(acc)

def two():
    lines, acc = setup()
    for row, l in enumerate(lines):
        for col, c in enumerate(l):
            if c == 'A':
                l = lines[row - 1][col - 1] + c + lines[row + 1][col + 1]
                r = lines[row + 1][col - 1] + c + lines[row - 1][col + 1]
                if l in ['MAS', 'SAM'] and r in ['MAS', 'SAM']:
                    acc += 1
    print(acc)

one()
two()

[–] [email protected] 3 points 20 hours ago

Haskell

Popular language this year :)

I got embarrassingly stuck on this one trying to be clever with list operations. Then I realized I should just use an array...

import Data.Array.Unboxed (UArray)
import Data.Array.Unboxed qualified as A
import Data.Bifunctor

readInput :: String -> UArray (Int, Int) Char
readInput s =
  let rows = lines s
      n = length rows
   in A.listArray ((1, 1), (n, n)) $ concat rows

s1 `eq` s2 = s1 == s2 || s1 == reverse s2

part1 arr = length $ filter isXmas $ concatMap lines $ A.indices arr
  where
    isXmas ps = all (A.inRange $ A.bounds arr) ps && map (arr A.!) ps `eq` "XMAS"
    lines p = [take 4 $ iterate (bimap (+ di) (+ dj)) p | (di, dj) <- [(1, 0), (0, 1), (1, 1), (1, -1)]]

part2 arr = length $ filter isXmas innerPoints
  where
    innerPoints =
      let ((i1, j1), (i2, j2)) = A.bounds arr
       in [(i, j) | i <- [i1 + 1 .. i2 - 1], j <- [j1 + 1 .. j2 - 1]]
    isXmas p = up p `eq` "MAS" && down p `eq` "MAS"
    up (i, j) = map (arr A.!) [(i + 1, j - 1), (i, j), (i - 1, j + 1)]
    down (i, j) = map (arr A.!) [(i - 1, j - 1), (i, j), (i + 1, j + 1)]

main = do
  input <- readInput <$> readFile "input04"
  print $ part1 input
  print $ part2 input

[–] LeixB 3 points 21 hours ago* (last edited 17 hours ago)

Haskell

import Control.Arrow
import Data.Array.Unboxed
import Data.List

type Pos = (Int, Int)
type Board = Array Pos Char
data Dir = N | NE | E | SE | S | SW | W | NW

target = "XMAS"

parse s = listArray ((1, 1), (n, m)) [l !! i !! j | i <- [0 .. n - 1], j <- [0 .. m - 1]]
  where
    l = lines s
    (n, m) = (length $ head l, length l)

move N = first pred
move S = first succ
move E = second pred
move W = second succ
move NW = move N . move W
move SW = move S . move W
move NE = move N . move E
move SE = move S . move E

check :: Board -> Pos -> Int -> Dir -> Bool
check b p i d =
    i >= length target
        || ( inRange (bounds b) p
                && (b ! p) == (target !! i)
                && check b (move d p) (succ i) d
           )

checkAllDirs :: Board -> Pos -> Int
checkAllDirs b p = length . filter (check b p 0) $ [N, NE, E, SE, S, SW, W, NW]

check2 :: Board -> Pos -> Bool
check2 b p =
    all (inRange (bounds b)) moves && ((b ! p) == 'A') && ("SSMM" `elem` rotations)
  where
    rotations = rots $ (b !) <$> moves
    moves = flip move p <$> [NE, SE, SW, NW]

    rots xs = init $ zipWith (++) (tails xs) (inits xs)

part1 b = sum $ checkAllDirs b <$> indices b
part2 b = length . filter (check2 b) $ indices b

main = getContents >>= print . (part1 &&& part2) . parse

[–] [email protected] 2 points 19 hours ago

C#

public class Day04 : Solver
{
  private int width, height;
  private char[,] data;

  public void Presolve(string input) {
    var lines = input.Trim().Split("\n").ToList();
    height = lines.Count;
    width = lines[0].Length;
    data = new char[height, width];
    for (int i = 0; i < height; i++) {
      for (int j = 0; j < width; j++) {
        data[i, j] = lines[i][j];
      }
    }
  }

  private static readonly string word = "XMAS";

  public string SolveFirst()
  {
    int counter = 0;
    for (int start_i = 0; start_i < height; start_i++) {
      for (int start_j = 0; start_j < width; start_j++) {
        if (data[start_i, start_j] != word[0]) continue;
        for (int di = -1; di <= 1; di++) {
          for (int dj = -1; dj <= 1; dj++) {
            if (di == 0 && dj == 0) continue;
            int end_i = start_i + di * (word.Length - 1);
            int end_j = start_j + dj * (word.Length - 1);
            if (end_i < 0 || end_j < 0 || end_i >= height || end_j >= width) continue;
            for (int k = 1; k < word.Length; k++) {
              if (data[start_i + di * k, start_j + dj * k] != word[k]) break;
              if (k == word.Length - 1) counter++;
            }
          }
        }
      }
    }
    return counter.ToString();
  }

  public string SolveSecond()
  {
    int counter = 0;
    for (int start_i = 1; start_i < height - 1; start_i++) {
      for (int start_j = 1; start_j < width - 1; start_j++) {
        if (data[start_i, start_j] != 'A') continue;
        int even_mas_starts = 0;
        for (int di = -1; di <= 1; di++) {
          for (int dj = -1; dj <= 1; dj++) {
            if (di == 0 && dj == 0) continue;
            if ((di + dj) % 2 != 0) continue;
            if (data[start_i + di, start_j + dj] != 'M') continue;
            if (data[start_i - di, start_j - dj] != 'S') continue;
            even_mas_starts++;
          }
        }
        if (even_mas_starts == 2) counter++;
      }
    }
    return counter.ToString();
  }
}

[–] [email protected] 1 points 17 hours ago

Rust

One of those with running through tricky grid indices. The vector types from the euclid crate helped in dealing with positions.

Code

use euclid::{vec2, default::*};

fn count_xmas(grid: &[&[u8]], pos: (usize, usize)) -> u32 {
    if grid[pos.1][pos.0] != b'X' {
        return 0
    }

    let bounds = Rect::new(Point2D::origin(), Size2D::new(grid[0].len() as i32, grid.len() as i32));
    const DIRS: [Vector2D<i32>; 8] = [
        vec2(1, 0), vec2(-1, 0), vec2(0, 1), vec2(0, -1),
        vec2(1, 1), vec2(1, -1), vec2(-1, 1), vec2(-1, -1),
    ];
    let mut count = 0;
    for dir in DIRS {
        let mut cur = Point2D::from(pos).to_i32();
        let mut found = true;
        for letter in [b'M', b'A', b'S'] {
            cur += dir;
            if !bounds.contains(cur) || grid[cur.y as usize][cur.x as usize] != letter {
                found = false;
                break
            }
        }
        if found {
            count += 1;
        }
    }
    count
}

fn part1(input: String) {
    let grid = input.lines().map(|l| l.as_bytes()).collect::<Vec<_>>();    
    let count = (0..grid.len()).map(|y| {
            (0..grid[y].len()).map(|x| count_xmas(&grid, (x, y))).sum::<u32>()
        })
        .sum::<u32>();
    println!("{count}");
}

fn is_x_mas(grid: &[&[u8]], pos: (usize, usize)) -> bool {
    if grid[pos.1][pos.0] != b'A' {
        return false
    }

    const DIRS: [Vector2D<i32>; 4] = [vec2(1, -1), vec2(1, 1), vec2(-1, 1), vec2(-1, -1)];
    let pos = Point2D::from(pos).to_i32();
    (0..4).any(|d| {
        let m_pos = [pos + DIRS[d], pos + DIRS[(d + 1) % 4]]; // 2 adjacent positions of M
        let s_pos = [pos + DIRS[(d + 2) % 4], pos + DIRS[(d + 3) % 4]]; // others S
        m_pos.iter().all(|p| grid[p.y as usize][p.x as usize] == b'M') &&
        s_pos.iter().all(|p| grid[p.y as usize][p.x as usize] == b'S')
    })
}

fn part2(input: String) {
    let grid = input.lines().map(|l| l.as_bytes()).collect::<Vec<_>>();    
    let count = (1..grid.len() - 1).map(|y| {
            (1..grid[y].len() - 1).filter(|&x| is_x_mas(&grid, (x, y))).count()
        })
        .sum::<usize>();
    println!("{count}");
}

util::aoc_main!();

(also on github)

[–] [email protected] 1 points 17 hours ago (1 children)

I tried to think of some clever LINQ to do this one, but was blanking entirely.

So naïve search it is.

C#

string wordsearch = "";
int width;
int height;

public void Input(IEnumerable<string> lines)
{
  wordsearch = string.Join("", lines);
  height = lines.Count();
  width = lines.First().Length;
}

public void Part1()
{
  int words = 0;
  for (int y = 0; y < height; y++)
    for (int x = 0; x < width; x++)
      words += SearchFrom(x, y);

  Console.WriteLine($"Words: {words}");
}
public void Part2()
{
  int words = 0;
  for (int y = 1; y < height - 1; y++)
    for (int x = 1; x < width - 1; x++)
      words += SearchCross(x, y);

  Console.WriteLine($"Crosses: {words}");
}

public int SearchFrom(int x, int y)
{
  char at = wordsearch[y * width + x];
  if (at != 'X')
    return 0;

  int words = 0;
  for (int ydir = -1; ydir <= 1; ++ydir)
    for (int xdir = -1; xdir <= 1; ++xdir)
    {
      if (xdir == 0 && ydir == 0)
        continue;

      if (SearchWord(x, y, xdir, ydir))
        words++;
    }

  return words;
}

private readonly string word = "XMAS";
public bool SearchWord(int x, int y, int xdir, int ydir)
{
  int wordit = 0;
  while (true)
  {
    char at = wordsearch[y * width + x];
    if (at != word[wordit])
      return false;

    if (wordit == word.Length - 1)
      return true;

    wordit++;

    x += xdir;
    y += ydir;

    if (x < 0 || y < 0 || x >= width || y >= height)
      return false;
  }
}

public int SearchCross(int x, int y)
{
  if (x == 0 || y == 0 || x == width - 1 || y == width - 1)
    return 0;

  char at = wordsearch[y * width + x];
  if (at != 'A')
    return 0;

  int found = 0;
  for (int ydir = -1; ydir <= 1; ++ydir)
    for (int xdir = -1; xdir <= 1; ++xdir)
    {
      if (xdir == 0 || ydir == 0)
        continue;

      if (wordsearch[(y + ydir) * width + (x + xdir)] != 'M')
        continue;
      if (wordsearch[(y - ydir) * width + (x - xdir)] != 'S')
        continue;

      found++;
    }

  if (found == 2)
    return 1;

  return 0;
}

[–] [email protected] 1 points 17 hours ago

I haven't quite started yet, and this one does feel like a busy work kinda problem. I was wondering if I could write something to rotate the board and do the search, but I think that might be not worth the effort

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