local letters = {"d", "e", "e", "g", "k", "l", "n", "o","w"}
local word_list = "unixdict.txt"  -- local copy
local nl = os.platform == "windows" ? "\r\n" : "\n"
local words = io.contents(word_list):rstrip():split(nl)
-- Get rid of words under 3 letters or over 9 letters.
words = words:filter(|w| -> 2 < #w < 10):reorder()
local found = {}
for words as word do
    if "k" in word then
        local lets = letters:clone()
        local ok = true
        for i = 1, #word do
            local c = word[i]
            local ix = lets:findindex(|e| -> e == c)
            if !ix then
                ok = false
                break
            end
            lets:remove(ix)
        end
        if ok then found:insert(word) end
    end
end

print($"The following {#found} words are the solutions to the puzzle:")
print(found:concat(nl))

-- Optional extra.
local most_found = 0
local most_words9 = {}
local most_letters = {}
-- Iterate through all 9 letter words in the dictionary.
for words:filtered(|w| -> #w == 9) as word9 do
    letters = word9:split(""):sort()
    -- Get distinct letters.
    local distinct_letters = letters:dedup():reorder()
    -- Place each distinct letter in the middle and see what we can do with the rest.
    for distinct_letters as letter do
        found = 0
        for words as word do
            if word:find(letter, 1, true) then
                local lets = letters:clone()
                local ok = true
                for i = 1, #word do
                    local c = word[i]
                    local ix = lets:findindex(|e| -> e == c)
                    if !ix then
                        ok = false
                        break
                    end
                    lets:remove(ix)
                end
                if ok then found += 1 end
            end
        end
        if found > most_found then
            most_found = found
            most_words9 = {word9}
            most_letters = {letter}
        elseif found == most_found then
            most_words9:insert(word9)
            most_letters:insert(letter)
        end
    end
end
print($"\nMost words found = {most_found}")
print("Nine letter words producing this total:")
for i = 1, #most_words9 do
    print($"{most_words9[i]} with central letter '{most_letters[i]}'")
end