Complexity 應該係要講個problem itself 多過邊範 好似Netflix google 個啲 佢地啲frontend 都整得好好
只係香港無可否認太多人淨係做crud , complexity 太低, 好似考Java 咁問深少少(其實都好basic) eg oom vs stackoverfow, jvm, jvm heap vs stack都答不到, 更何況synchronised vs reentrantlock, blocking vs non-blocking 入面點行