【高级技巧】Lua蓄水池抽样：沙巴克报名名单等概率抽10人

local function pick10(actor, names)
    for i = 1, 10 do
        local j = math.random(1, #names)   -- 长度未知会出错
        setplayvar(getplayerbyname(names[j]), "SBK_TRY", 1)
    end                                    -- 还会重复抽同一人
end

local function reservoir(actor, names, k)
    local pool = {}
    for i, name in ipairs(names) do
        if i <= k then
            pool[i] = name
        else
            local r = math.random(1, i)
            if r <= k then pool[r] = name end   -- 1/i 概率换入
        end
    end
    for j = 1, #pool do
        setplayvar(getplayerbyname(pool[j]), "SBK_TRY", 1)
    end
    sendmsg(actor, 1, "沙巴克体验资格抽出 " .. #pool .. " 人")
end