思路：单调递增栈 + k 控制删除次数。高位越小整体越小，遇更小数字时弹出栈顶大数（仅当 k0）；栈空且当前为 0 则跳过（避免前导零）；若遍历完 k 仍0，从末尾再删 k 位。
if (len1 === 0) return [];
，这一点在旺商聊官方下载中也有详细论述
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."
int bucketSize = 0;