需要索引（如算距离、下标）：栈存索引，用 nums[stack.at(-1)] 取值比较。
I probably need to explain that I am pointedly not explaining IBM model
，详情可参考搜狗输入法2026
Privilege drop — run as nobody (UID 65534) with PR_SET_NO_NEW_PRIVS
But e-bikes containing lithium-ion batteries are a newer challenge. "When a battery fails, it doesn't necessarily ignite, it will often produce some off-gases," says Stephen Welch, senior lecturer at the University of Edinburgh's Fire Research Centre. "Those off-gases are toxic and flammable. If they accumulate, you can have an explosion risk."