1.--dense_rank()分析函数(查找每个部门工资最高前三名员工信息) select * from (select deptno,ename,sal,dense_rank() over(partition by deptno order by sal desc) a from scott.emp) where a<=3 order by deptno asc,sal desc ; 结果: --rank()分析函数(运行结果与上语句相同) select * from (select dep…
Least Crucial Node 题目链接: http://acm.hust.edu.cn/vjudge/contest/127401#problem/C Description http://7xjob4.com1.z0.glb.clouddn.com/e15d7d11650607e5795d28e1120d7109 Input There are several input lines to a test case. The first line of each test case co…
Is It A Tree? 题目链接: http://acm.hust.edu.cn/vjudge/contest/123393#problem/M Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfy…