在测试环境中使用某个账号ESCMOWNER对数据库进行ALTER操作时,老是报如下错误: ORA-00604: error occurred at recursive SQL level 1 ORA-20016: (ALTER) Action denied as it is a protected object! ORA-06512: at line 7 不清楚发生了什么情况,于是想跟踪当前会话,查看具体原因,查看当前会话的SID为967 SELECT USERENV('SID') FROM D…

在scala中如果一个函数在最后一步调用自己(必须完全调用自己,不能加其他额外运算子),那么在scala中会复用函数栈,这样递归调用就转化成了线性的调用,效率大大的提高.If a function calls itself as its last action, the function's stack frame can be reused. This is called tail recursion.=> Tail recursive functions are iterative proc…

one recursive approach to solve hdu 1016, list all permutations, solve N-Queens puzzle. reference: the video of stanford cs106b lecture 10 by Julie Zelenski https://www.youtube.com/watch?v=NdF1QDTRkck // hdu 1016, 795MS #include <cstdio> #include &l…

thanks prof. Abhiram Ranade for his vedio on Longest Common Subsequence 's back track search view in lecture 19, nice explanation indeed. // back track, recursive, 390 ms, O(m*n) memory #include <cstdio> #include <vector> #include <string&g…

1. Write a procedure count-list to count the number of elements in a list (defun count-list (numbers) ( (+ (count-list (rest numbers))))) (print (count-list '(1 2 3)))5 6 result: 3 2. Write a procedure reverse-list to reverse each word in a list of w…

Binary Tree Preorder Traversal Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,2,3]. Note: Recursive solution is trivial, could you do it iteratively? ''' Created o…

WITH RECURSIVE and MySQL If you have been using certain DBMSs, or reading recent versions of the SQL standard, you are probably aware of the so-called “WITH clause” of SQL. Some call it Subquery Factoring. Others call it Common Table Expression. A fo…

http://www.postgresonline.com/journal/archives/131-Using-Recursive-Common-table-expressions-to-represent-Tree-structures.html Tree Problem and was based on PostgreSQL 7.4 technology. We'll repeat the text here for completeness and demonstrate the Pos…

Recursive sequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Problem Description Farmer John likes to play mathematics games with his N cows. Recently, they are attracted by recursive sequences. In each turn,…

Recursive sequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 249    Accepted Submission(s): 140 Problem Description Farmer John likes to play mathematics games with his N cows. Recently, t…