longtails的博客

lt20 生成括号，回溯https://longtails.blog.youkuaiyun.com/article/details/122910119

lt22. 括号生成回溯题解package lt100func generateParenthesis(n int) []string { return backTracing("", n, n)}/**回溯，因为只有两个符号1. () （的位置必须比)小，递归过程中保证了全部2. 没有到最后，(不能全部用光 if left==0 and right>1 可以直接跳过去3. 不需要验证合法性，因为剪枝完成后，只有有效的了*/func backTracing(result

143. 重排链表给定一个单链表 L：L0→L1→…→Ln-1→Ln ，将其重新排列后变为： L0→Ln→L1→Ln-1→L2→Ln-2→…你不能只是单纯的改变节点内部的值，而是需要实际的进行节点交换。示例 1:给定链表 1->2->3->4, 重新排列为 1->4->2->3.示例 2:给定链表 1->2->3->4->5, 重新排列为 1->5->2->4->3.package mainimport

1102. Invert a Binary Tree (25)1102.总结：初始化工作分离，单独出来。

PAT-A-1101. Quick Sort (25)注意输出为0,第二行为空，需要输出一个回车

55. Jump GameGiven

143. Reorder List

1106. Lowest Price in Supply Chain (25)运行超时，采取策略建立备忘录

344、reverse string//注意ｃ串的结尾#include<iostream>#include <cstring>#include<string>using namespace std;string reverseString(string s) { int size=s.length(); //必须为c串提供结尾\0空间 char *c=new cha

Pat1002 A+B for Polynomials(25) This time, you are supposed to find A+B where A and B are two polynomials.

题目信息 1110. Complete Binary Tree (25)Given a tree, you are supposed to tell if it is a complete binary tree.Input Specification:Each input file contains one test case. For each case, the first line give

pat 1109Group Photo (25)

1108. Finding Average (20)

PAT A 1105

PAT(A) 1104A. Sum of Number Segments (20)

PAT 1105. Spiral Matrix (25)

1112. Stucked Keyboard (20)

1113. Integer Set Partition (25)

1115. Counting Nodes in a BST (30) 二叉搜索树，计算叶子结点和其父结点的个数和。需要先构建该二叉树。

1116. Come on! Let’s C (20)待续

1117. Eddington Number(25)待续

1118. Birds in Forest (25)查并集

1119. Pre- and Post-order Traversals (30)考察二叉树的几种遍历方式

1004. Counting Leaves (30) 树

1003. Emergency (25) 图

1111. Online Map (30)Input our current position and a destination, an online map can recommend several paths. Now your job is to recommend two paths to your user: one is the shortest, and the other is

1107. Social Clusters (30)很明显，这道题是考察并查集，但有点不同的是，反过来了，查的不是，hobby的分组，而是查人数的分组。反过来记录即可。[PAT_A1118那个查并集比较直接，不用在反转以下思维](http://blog.youkuaiyun.com/scylhy/article/details/52745290)

1006. Sign In and Sign Out (25) scanf("%s %02d:%02d:%02d %02d:%02d:%02d",id,&a,&b,&c,&d,&e,&f);//这方法很好，注意是int*

1007. Maximum Subsequence Sum (25)

1008. Elevator (20)

1009. Product of Polynomials (25)

1013. Battle Over Cities (25)It is vitally important to have all the cities connected by highways in a war. If a city is occupied by the enemy, all the highways from/toward that city are closed. We mus

1014. Waiting in Line (30)Suppose a bank has N windows open for service. There is a yellow line in front of the windows which devides the waiting area into two parts. The rules for the customers to wai

1010. Radix (25)

1100. Mars Numbers (20)字符串处理 getchar() getline() strtok()

1016. Phone Bills (25) 排序　on-off

1018. Public Bike Management (30)最短距离DFS ,dijkstra

1017. Queueing at Bank (25)银行队列模型　8:00-17:00

1019. General Palindromic Number (20)A number that will be the same when it is written forwards or backwards is known as a Palindromic Number. For example, 1234321 is a palindromic number. All single d

PAT_A 1020. Tree Traversals (25)Suppose that all the keys in a binary tree are distinct positive integers. Given the postorder and inorder traversal sequences, you are supposed to output the level orde