08 Julia

$ julia script.jl

# conveniently read the file into an array of lines
lines = readlines("08.input")

# the border of the forest
count = 2*length(lines[1]) + 2*length(lines) - 4

# iterate over inner rows
for n in 2:length(lines)-1
    # the current row
    row = lines[n]
    # iterate over inner columns
    for m in 2:length(row)-1
        # the current tree, use ASCII of number as its height
        hnm = Int(lines[n][m])

        # check the column above the tree
        t = true
        for i in 1:(n-1)
            # compare ASCII values
            if Int(lines[i][m]) >= hnm
                t = false
                # view is blocked, skip
                break
            end
        end

        # check the column below
        b = true
        for i in (n+1):length(lines)
            if Int(lines[i][m]) >= hnm
                b = false
                break
            end
        end

        # check the beginning of the current row
        l = true
        for i in 1:(m-1)
            if Int(lines[n][i]) >= hnm
                l = false
                break
            end
        end

        # check the rest of the current row
        r = true
        for i in (m+1):length(row)
            if Int(lines[n][i]) >= hnm
                r = false
                break
            end
        end

        # if visible from any angle, count the tree in
        if t || b || r || l
            global count += 1
        end
    end
end

println("Visible trees ", count)

lines = readlines("08.input")
score = 0

for n in 2:length(lines)-1
    row = lines[n]
    for m in 2:length(row)-1
        hnm = Int(lines[n][m])

        t = 0 # view up (top)
        for i in (n-1):-1:1
            t += 1
            # count until there is a blocking tree
            if Int(lines[i][m]) >= hnm
                break
            end
        end

        b = 0 # view down (bottom)
        for i in (n+1):length(lines)
            b += 1
            if Int(lines[i][m]) >= hnm
                break
            end
        end

        l = 0 # view left
        for i in (m-1):-1:1
            l += 1
            if Int(lines[n][i]) >= hnm
                break
            end
        end

        r = 0 # view right
        for i in (m+1):length(row)
            r += 1
            if Int(lines[n][i]) >= hnm
                break
            end
        end

        mult = t * b * r * l
        if mult > score
            global score = mult
        end
    end
end

println("Maximum score ", score)