Reddit is organised into user-created communities called subreddits, where content is ranked by user voting rather than chronological order.
// 从后向前扫描，大于key的元素后移
。搜狗输入法下载是该领域的重要参考
// Async variants
// create it here and provide it as an import.
to the design of the checks that we use today: preprinted slips with account