Advent of code - Day 6 - Lua

day6.lua

mem = {[1] = "0 5 10 0 11 14 13 4 11 8 8 7 1 4 12 11"}
--mem = {[0] = "0 2 7 0"}

function split(str)
    local ret = {}
    local i = 1
    for text in string.gmatch(str, "%S+") do
        ret[i] = tonumber(text)
        i = i + 1
    end
    return ret
end

function step(str)
    ret = split(str)
    
    local max = 1
    for i=1, #ret do
        if ret[i] > ret[max] then
            max = i
        end
    end
    
    local all = math.floor(ret[max] / #ret)
    local remainder = ret[max] % #ret
    ret[max] = 0
    
    for i=1, #ret do
        local b = (i + max) % #ret
        b = (b == 0 and #ret or b)
        ret[b] = ret[b] + all + (i <= remainder and 1 or 0)
    end
    
    return table.concat(ret, " ")
end
found = -1
while found == -1 do
    local m = step(mem[#mem])
    print(#mem + 1, m)
    for i=1, #mem do
        if (mem[i] == m) then
            found = i
        end
    end
    mem[#mem + 1] = m
end
print("Start", "End", "Length")
print(found - 1, #mem - 1, #mem - found)