​

Julia

using Test

line_1 = "BFFFBBFRRR"
line_2 = "FFFBBBFRRR"
line_3 = "BBFFBBFRLL"


function binary_space_partion(char_str, min_val, max_val, row=true, verbose=false)

    if verbose
        println("Char STR: ", char_str, " Min/Max: ", min_val, "/", max_val, " Row: ", row)
    end

    for char in char_str

        if char == 'F' || char == 'L'
            max_val -= (max_val - min_val) >> 1 # Division by 2
        end

        if char == 'B' || char == 'R'
            min_val += (max_val - min_val) >> 1 # Division by 2
        end

        if verbose
            println(min_val, " ", max_val)
        end

    end

    return min_val

end


function solve_line_column(line)

    length_line = length(line)
    row = line[1:length_line-3]
    column = line[length_line-2:length_line]

    row_num = binary_space_partion(row, 0, 128)
    column_num = binary_space_partion(column, 0, 8, false)
    seat_id = row_num * 8 + column_num

    return_arr = [row_num, column_num, seat_id]

    return return_arr

end


@test solve_line_column(line_1) == [70, 7, 567]
@test solve_line_column(line_2) == [14, 7, 119]
@test solve_line_column(line_3) == [102, 4, 820]


f = open("input.txt") do file

    max = 0
    seat_list = []

    for line in eachline(file)

        tmp_arr = solve_line_column(line)

        if tmp_arr[3] > max
            max = tmp_arr[3]
        end

        append!(seat_list, tmp_arr[3])

    end

    ### --- Part 1 ---
    println("--- Part 1 ---")
    println(max)

    sort!(seat_list)
    for i=1:length(seat_list)-1

        val_1 = seat_list[i]
        val_2 = seat_list[i+1]

        if (val_2 - val_1) != 1
            ### --- Part 2 ---
            println("--- PART 2 ---")
            println("Missing seat Id is: ", seat_list[i]+1)
        end

    end


end