Lua素数筛：倍数划除的批量判定

-- 错误：每个数逐个试除判定，重复劳动成堆
local function isPrime(n)
    for d = 2, n - 1 do
        if n % d == 0 then return false end
    end
    return true
end

local function sieve(n)
    local isP = {}
    for i = 2, n do isP[i] = true end
    local out = {}
    for i = 2, n do
        if isP[i] then
            out[#out + 1] = i
            for j = i * i, n, i do
                isP[j] = false
            end
        end
    end
    return out
end
local label = panel:getChildByName("primeText")
label:setString(table.concat(sieve(30), ","))