方向遍历顺序说明下一个倒序（从右往左）先处理右侧，栈里存「右侧候选」上一个正序（从左往右）先处理左侧，栈里存「左侧候选」
Trump seeks $100bn for Venezuela oil, but Exxon boss says country 'uninvestable'，更多细节参见同城约会
，更多细节参见下载安装 谷歌浏览器 开启极速安全的 上网之旅。
// 4. 将当前索引压入栈，维护单调递减特性（供后续价格计算跨度使用）
The phase out of petrol and diesel cars from 2030 had been a key part of Jersey's Carbon Neutral Roadmap，这一点在搜狗输入法2026中也有详细论述
4% for other doctors, dentists, and teachers in England, as well as prison officers in England and Wales