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」
config extensions objects refs state tmp，更多细节参见旺商聊官方下载
Appearing in neutral tones like khaki and beige, the looks were a throwback to the grunge-inspired styles of the 90s.，推荐阅读爱思助手下载最新版本获取更多信息
Officially, Venezuela has 300 billion barrels of oil reserves – yet in 2023, it exported just 211.6 million barrels of oil, worth about $4bn. Compare that to second-placed Saudi Arabia, which has 267 billion barrels of reserves, but had exports worth $181bn in the same time period.