Lua数字根：数位累加的模九捷径

local function rootSlow(n)
    while n >= 10 do
        local s = 0
        while n > 0 do
            s = s + n % 10
            n = math.floor(n / 10)
        end
        n = s
    end
    return n
end

local function rootFast(n)
    if n == 0 then return 0 end
    local r = n % 9
    return r == 0 and 9 or r
end
local p = getplayerbyname("root01")
sendmsg(p, 1, rootSlow(8888) .. " 与 " .. rootFast(8888))