day8.jl

using DelimitedFiles
cd("/Users/patricklauer/Documents/GitHub/advent_of_code_2023/")
lines = readdlm("day8_input.txt") 

## seperate directions
directions = lines[1]
directions = collect(directions)
## seperate and clean map information
map = lines[2:end,:]
map = map[:, [1,3,4]]

function remove_symbols(matrix)
    return replace(matrix, r"[\(,\)]" => "")
end

map[:,2] = remove_symbols.(map[:,2])
map[:,3] = remove_symbols.(map[:,3])

map
## first column = location
## second column = location if left step
## third column = location if right step    


## while loop through matrix till it reaches ZZZ and keep track of steps
directions = repeat(directions, 100) 
location = "AAA"
steps = 0

while location != "ZZZ"

    i = findfirst( x -> x == 1, map[:,1] .== location) ## find the row in which the correct location is in the matrix

    if directions[steps+1] == 'L'

        location = map[i,2]
        steps += 1

    elseif directions[steps+1] == 'R'
    
        location = map[i,3]
        steps += 1
    end
end


## Part B

## loop through all elements that end with A and track the steps they need to reach ZZZ
## find least common multiplicate of the steps 

count_steps = function(map, direction, location)

    steps = 0

    while endswith.(location, "Z") != true
     
        i = findall( x -> x == 1, map[:,1] .== location) ## find the row in which the correct location is in the matrix
    
        if directions[steps+1] == 'L'

            location = map[i,2][1]

         elseif directions[steps+1] == 'R'
    
            location = map[i,3][1]
        end

        steps += 1

    end
    return steps
end


directions = repeat(directions, 100000) 
locations = String.([s for s in map[:,1] if endswith(s, "A")])
all_steps = []


for i in 1:length(locations)

    push!(all_steps, count_steps(map, directions, locations[i]))

end

all_steps

## find least common multiplicate
reduce(lcm, all_steps)