http://poj.org/problem?id=3974 题目大意: 求最大回文子串长度. ———————————————————— 马拉车板子题. 马拉车大概讲解: 首先在每两个字母之间插入‘#’ id为一个回文串的中点,mx为该串的右端点,p[i]为以i为中点的回文串长度. 假设我们求完了上述的mx和id,枚举i的时候,我们有: if(mx>i)p[i]=min(p[2*id-i],mx-i); (显然i在该回文串中,左右对称可得该式子(如果i对称的点所在的回文串在id的回文串里面那么就…

Time Limit: 15000MS   Memory Limit: 65536K Total Submissions: 5121   Accepted: 1834 Description Andy the smart computer science student was attending an algorithms class when the professor asked the students a simple question, "Can you propose an eff…

本文版权归ljh2000和博客园共有,欢迎转载,但须保留此声明,并给出原文链接,谢谢合作. 本文作者:ljh2000 作者博客:http://www.cnblogs.com/ljh2000-jump/转载请注明出处,侵权必究,保留最终解释权! Description Andy the smart computer science student was attending an algorithms class when the professor asked the students a si…

Palindrome Time Limit: 15000MS   Memory Limit: 65536K Total Submissions: 13157   Accepted: 5028 Description Andy the smart computer science student was attending an algorithms class when the professor asked the students a simple question, "Can you pr…

题目大意就是说在给定的字符串里找出一个长度最大的回文子串. 才开始接触到manacher,不过这个算法的确很强大,这里转载了一篇有关manacher算法的讲解,可以去看看:地址 神器: #include <map> #include <set> #include <stack> #include <queue> #include <cmath> #include <ctime> #include <vector> #inc…

链接:点击这里 #include<iostream> #include<algorithm> #include<stdio.h> #include<cstring> using namespace std; #define maxn 1000005 #define LL long long #define ull unsigned long long ; ull p[maxn+],f[maxn],ff[maxn]; int main(){ p[]=; ;j&…

http://acm.timus.ru/problem.aspx?space=1&num=1297 https://vjudge.net/problem/URAL-1297 给定一个字符串,求最长回文子串. 论文题,摘一下论文的图片,保证一下就看懂了. (由于我摘不下来图片所以用了https://www.cnblogs.com/lidaxin/p/5002878.html的图片,代码也是参考的他) emm要是还没看懂的话稍微解释一下吧. 也就是说,实际上我们是把反串接到正串后面,然后后缀数组高度…

Manacher算法教程:http://blog.csdn.net/ggggiqnypgjg/article/details/6645824 模板题,Code 附带注释: #include<cstdio> #include<algorithm> #include<cstring> using namespace std; ],a[]; ]; ],zu;//f[i]表示插入一堆#后,以i为中心的最长回文子串の半径长度, //故其减1后就是原串的最长回文子串的答案 //也是…

考虑奇数长度的回文,对于字符串上的每个位置i,如果知道从i开始的后缀和到i为止的前缀反转后的字符串的lcp长度的话,也就知道了以第i个字符为对称中心的最长回文的长度了.因此,我们用在S中不会出现的字符将S和S反转后的字符串拼接起来,得到字符串S',计算S'的sa.于是,从i开始的后缀和到i为止的前缀反转后的字符串就都是S'中的后缀了,利用高度数组,可以轻易地求得它们最长公共前缀的长度. 对于长度为偶数的回文的处理也基本相同. 哈哈哈,MLE+TLE不可避. #include<cstdio> #…

这道题可以$O(nlogn)$,当然也可以$O(n)$做啦$qwq$ $O(nlogn)$的思路是枚举每个回文中心,通过哈希预处理出前缀和后缀哈希值备用,然后二分回文串的长度,具体的就是判断在长度范围内,前缀哈希值和后缀哈希值是否相等. #include<cstdio> #include<iostream> #include<algorithm> #include<cstring> #include<cmath> #include<ccty…

传送门 求一个串的最长回文子串的长度 1.后缀数组 把这个串反转后接到原串的后面,中间连一个没有出现过的字符. 然后求这个新字符串的某两个后缀的公共前缀的最大值即可. ——代码 #include <cstdio> #include <cstring> #include <iostream> #define N 2000010 #define max(x, y) ((x) > (y) ? (x) : (y)) int n, m, len, ans; int buc[…

题目链接:http://poj.org/problem?id=3974 题目: 多组询问,每组给出一个字符串,求该字符串最长回文串的长度 数据范围支持$O(nlog n)$ 解法一: 二分+hash 回文串分奇数串和偶数串.对于奇数串,我们枚举它的中点,二分一下这个中点可以向两边扩展多远的距离:对于偶数串,我们枚举它中间两个点靠左的点,同样二分可以扩展的距离,这样时间复杂度就是$O(nlog n)$的了 说起来容易,写起来不是很容易 解法二: 每次跑一遍manacher就好了 说起来容易,写起来…

之前用字符串hash+二分过了,今天刚看了manacher拿来试一试. 这manacher也快太多了%%% #include <iostream> #include <cstring> #include <cstdio> #include <algorithm> using namespace std; ; *maxn]; ], id, mx, ans; inline void manacher(){ mx = id = ans = ; memset( p,…

题目: Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example, "A man, a plan, a canal: Panama" is a palindrome. "race a car" is not a palindrome. Note: Have you consider…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…

9. Palindrome Number Easy Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121 Output: false Explanation: From left to right, it…

第一周: 经过漫长的时间,终于有时间来写一下结题报告. 地址http://acm.hust.edu.cn/vjudge/contest/view.action?cid=36180#overview A:POJ 1837       Balance      按偏移量DP                                                   题解 B:POJ 1948        Triangular Pastures   按边长DP                …

A. Karen and Morning time limit per test 2 seconds  memory limit per test 512 megabytes input standard input output standard output Karen is getting ready for a new school day! It is currently hh:mm, given in a 24-hour format. As you know, Karen love…

本文出自   http://blog.csdn.net/shuangde800 刘汝佳<算法竞赛入门经典-训练指南>的动态规划部分的习题Beginner  打开 这个专题一共有25题,刷完后对dp的感觉提升了不少. 现把解题报告整理了一下,希望对大家能有帮助. 入门习题 (Exercises: Beginner) UVa11584 Partitioning by Palindromes 入门题目 LA4256 Salesman 入门题目 UVa10534 Wavio Sequence 可以转化…

双指针基础 双指针(Two Pointers)是面对数组.链表结构的一种处理技巧.这里“指针”是泛指,不但包括通常意义上的指针,还包括索引.迭代器等可用于遍历的游标. 同方向指针 设定两个指针.从头往尾(或从尾到头)遍历,我称之为同方向指针,第一个指针用于遍历,第二个指针满足一定条件下移动.例如 LeetCode题目 283. Move Zeroes: // 283. Move Zeroes void moveZeroes(vector<int>& nums) { ; ;j<nu…

前言   [LeetCode 题解]系列传送门:  http://www.cnblogs.com/double-win/category/573499.html   1.题目描述 Determine whether an integer is a palindrome. Do this without extra space. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of c…

Palindrome Time Limit: 15000MS   Memory Limit: 65536K Total Submissions: 14021   Accepted: 5374 题目链接:http://poj.org/problem?id=3974 Description: Andy the smart computer science student was attending an algorithms class when the professor asked the st…

[题解]Palindrome pairs [Codeforces159D] 传送门:\(Palindrome\) \(pairs\) \([CF159D]\) [题目描述] 给定一个长度为 \(N\) 的字符串 \(S\),求有多少四元组 \((l_1,r_1,l_2,r_2)\) 满足 \(1 \leqslant l_1 \leqslant r_1 \leqslant l_2 \leqslant r_2 \leqslant N\) 且 \(S[l1...r1],\) \([Sl2...r2]\…

题目来源 https://leetcode.com/problems/valid-palindrome/ Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car"…

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…

http://poj.org/problem?id=3974 Palindrome Time Limit: 15000MSMemory Limit: 65536K Total Submissions: 2707Accepted: 995 Description Andy the smart computer science student was attending an algorithms class when the professor asked the students a simpl…

Palindrome Time Limit: 15000MS   Memory Limit: 65536K Total Submissions: 3280   Accepted: 1188 Description Andy the smart computer science student was attending an algorithms class when the professor asked the students a simple question, "Can you pro…

[题目描述] Implement a function to check if a linked list is a palindrome. 设计一种方式检查一个链表是否为回文链表. [题目链接] www.lintcode.com/en/problem/palindrome-linked-list/ [题目解析] 假设一个链表是回文,那么把链表分割为1-n/2,n/2+1-n两个部分,这两个部分肯定是相同的(把第二部分顺序逆转过来或者逆转第一部分).所以如果我们能把任何一个部分的链表顺序逆转过来…

9. Palindrome Number 题目: Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? (ie, -1) If you are thinking of converting the integer to string, note the…

我现在在做一个叫<leetbook>的开源书项目,把解题思路都同步更新到github上了,需要的同学可以去看看 地址:https://github.com/hk029/leetcode 这个是书的地址:https://hk029.gitbooks.io/leetbook/ 009. Palindrome Number[E] 问题: Determine whether an integer is a palindrome. Do this without extra space. 思路 这里说不…