very_caiing

其实这篇也是PAT的题目，不过主要是用来学习Java字符串的操作的。今天看了Java编程思想字符串的章节，原来java里面String对象是永远不会变的，因为没有任何方法是修改字符串里面的数据的。如果要操作字符串对象例如：String str = "de";String s = "abc" + str + "fgh" + "00"; 理论上讲，第二个操作在执行过程中，每执行一次加

最近在学习JAVA，用题目练习一下，这道题目还是没有pass，一个case不行，一个case运行超时。主要学习的是复杂问题构造类的思路，另外是Comparator类的学习，如何将一个list进行sort。The ranklist of PAT is generated from the status list, which shows the scores of the sub

Today I review the DIJSKRA algorithm. Which is used to get the shortest length of all nodes in a map.The first step is :    to initial the result list 'res' and the sign list 'finRes', which marks whe

用英文描述一下思路吧...We are given a preorder list of tree, if it is a BST, then give the postorder list.I got some clue from the algorithm "how to get a tree from its preorder and inorder lists". It w

Today I studied the concept of Map in Java.In Map is described as : a group of key-value object pairs, allowing you to look up a value using a key. The ability to map objects to other objects can b

From this problem I learned that the how to traverse tree by level order.Here is the code of level traversal: Queue q = new LinkedList(); q.add(n); while (q.size() != 0) { n = q.poll();

最大连续子数列的问题：用了递归的解法，n长度的数列，先求得n-1的最大子数列，那么最大子数列要么是包含第n个数的数列，或者是不包含n的n-1的最大子数列。Given a sequence of K integers { N1, N2, ..., NK }. A continuous subsequence is defined to be { Ni, Ni+1, ...,

今天偷懒了，做了一道最简单的题目，，没什么好看得，但是应该是pass最快的一道题了。。为了证明今天做过了.....还是贴到这里来吧The highest building in our city has only one elevator. A request list is made up with N positive numbers. The numbers denote at