include("utils.jl")

function solution12_1()
    lines = non_empty_lines("12.data")
    adj_mat = Dict()
    for line in lines
        front, back = split(line, "-")
        push!(get!(adj_mat, front, []), back)
        push!(get!(adj_mat, back, []), front)
    end
    result = []
    growing = [["start"]]
    while length(growing) > 0
        new = []
        for path in growing
            for neighbour in get(adj_mat, last(path), 0)
                if Base.Unicode.isuppercase(neighbour[1])
                    push!(new, [path; neighbour])
                else
                    if neighbour == "end"
                       push!(result, [path; neighbour])
                    else
                        if !(neighbour in path)
                            push!(new, [path; neighbour])
                        end
                    end
                end
            end
        end
        growing = new
    end
    length(result)
end

function small_twice(path)
    length(filter(unique(path)) do element
        Base.Unicode.islowercase(element[1]) && length(filter(==(element), path)) > 1
    end) > 0
end


function solution12_2()
    lines = non_empty_lines("12.data")
    adj_mat = Dict()
    for line in lines
        front, back = split(line, "-")
        push!(get!(adj_mat, front, []), back)
        push!(get!(adj_mat, back, []), front)
    end
    result = []
    growing = [["start"]]
    while length(growing) > 0
        new = []
        for path in growing
            for neighbour in get(adj_mat, last(path), 0)
                if Base.Unicode.isuppercase(neighbour[1])
                    push!(new, [path; neighbour])
                else
                    if neighbour == "end"
                       push!(result, [path; neighbour])
                    else
                        if neighbour != "start" &&  (!small_twice(path) || !(neighbour in path))
                            push!(new, [path; neighbour])
                        end
                    end
                end
            end
        end
        growing = new
    end
    length(result)
end

solution12_2()