Package java.util.concurrent Description Utility classes commonly useful in concurrent programming. This package includes a few small standardized extensible frameworks, as well as some classes that provide useful functionality and are otherwise tedious or difficult to implement. Here are brief descriptions of the main components. See also the java.util.concurrent.locks and java.util.concurrent.atomic packages. Executors Interfaces. Executoris a simple standardized interface for defining custom thread-like subsystems, including thread pools, asynchronous I/O, and lightweight

Difference between count() 参考🔗： What is the Difference Between COUNT(*), COUNT(1), COUNT(column name), and COUNT(DISTINCT column name)? 很不错的文章，果然还是看英文靠谱点。 The COUNT() function belongs to SQL’s aggregate functions. It counts the number of rows that satisfy the criteria defined in the parentheses. It does not return the rows

LeetCode + 《剑指Offer II》刷题笔记。 图 图的搜索 如果要求在无权图中找出两个节点之间的最短距离，那么广度优先搜索可能是更合适的算法。 如果面试题要