AOC 2018 Solutions For Google Code-In

d1p1.jl

# Author: weCryOpen (Ruyi Li)

function d1p1(file)
    open(file) do f
        total = 0
        for line in eachline(f)
            # Iterate through each line in the file
            # Convert it to an integer, 
            n = parse(Int, line)
            # and add it to the total.
            total += n
        end
        # Return the total.
        total
    end
end

d1p2.jl

# Author: weCryOpen (Ruyi Li)

function d1p2(file)
    # Keep track of the list of instructions so we can
    # cycle over it again for future iterations.
    lst = Array{Int, 1}()

    # Keeps track of if a value is already present
    # within the set
    freq = Set{Int32}()
    curr = 0

    open(file) do f
        for line in eachline(f)
            # Iterate through each line in the file 
            # and convert it to an integer.
            n = parse(Int32, line)

            # Add it to the list of instructions.
            push!(lst, n)

            # Add the numbers to the current total
            curr += n

            # If the current number has already appeared,
            # stop the function early and return it.
            curr in freq && return curr

            # If not, add it to the set.
            push!(freq, curr)
        end
    end
    
    # Cycle through the instructions and perform the 
    # same tasks as earlier until we encounter a duplicate.
    for (_, n) in enumerate(Iterators.cycle(lst))
        curr += n
        curr in freq && return curr
        push!(freq, curr)
    end
end

d2p1.jl

# Author: weCryOpen (Ruyi Li)

function d2p1(file)
    open(file) do f
        # Keep track of the number of 2s and 3s
        twos = threes = 0
        for line in eachline(f)
            # Frequency Dictionary
            freq = Dict{Char, Int}()
            for chr in line
                # Loop through each character in each line
                # in the file
                if haskey(freq, chr)
                    # If the key exists, add 1 to it
                    freq[chr] += 1
                else 
                    # Otherwise, set it to 1
                    freq[chr] = 1
                end
            end
            # true evaluates to 1 and false to 0, so we 
            # can directly add the booleans to the
            # frequency trackers if 2 or 3 appear at least
            # once within the dictionary's values.
            twos += 2 in values(freq)
            threes += 3 in values(freq)
        end
        # Return the product of the frequencies.
        twos * threes
    end
end