【入门夯实】Lua集合交集：沙巴克双名单的重叠者识别

local function overlap(a, b)
    local out = {}
    for i = 1, #a do
        for j = 1, #b do             -- 200x200=4万次比较
            if a[i] == b[j] then out[#out + 1] = a[i] end
        end
    end
    return out
end

local function overlap(actor, a, b)
    local seen, out = {}, {}
    for i = 1, #a do seen[a[i]] = true end
    for j = 1, #b do
        if seen[b[j]] then
            out[#out + 1] = b[j]     -- 命中即交集
        end
    end
    sendmsg(actor, 1, "沙巴克双名单重叠 " .. #out .. " 人")
    return out
end