题目 Source http://acm.hdu.edu.cn/showproblem.php?pid=4080 Description Dr. Ellie Arroway has established contact with an extraterrestrial civilization. However, all efforts to decode their messages have failed so far because, as luck would have it, the…

题目链接:http://acm.hust.edu.cn/vjudge/problem/viewProblem.action?id=12580 [思路] 求出现次数不小于k次的最长可重叠子串和最后的出现位置. 法一: 后缀数组,二分长度,划分height.时间复杂度为O(nlogn) 法二: Hash法.构造字符串的hash函数,二分长度,求出hash(i,L)后排序,判断是否存在超过k个相同hash 值得块即可.时间为O(nlog2n).  法三:(UPD.16/4/6) SAM.求|right…

UVA 12206 - Stammering Aliens 题目链接 题意:给定一个序列,求出出现次数大于m,长度最长的子串的最大下标 思路:后缀数组.搞出height数组后,利用二分去查找就可以 这题之前还写过hash的写法也能过,只是写后缀数组的时候,犯了一个傻逼错误,把none输出成node还一直找不到...这是刷题来第二次碰到这样的逗比错误了,还是得注意. . 代码: #include <cstdio> #include <cstring> #include <alg…

Dr. Ellie Arroway has established contact with an extraterrestrial civilization. However, all efforts to decode their messages have failed so far because, as luck would have it, they have stumbled upon a race of stuttering aliens! Her team has found…

题意:找一个出现了m次的最长子串,以及这时的最右的位置. hash的话代码还是比较好写的,,但是时间比SA多很多.. #include <stdio.h> #include <algorithm> #include <string.h> using namespace std; + ; typedef long long ll; ; ; char s[N]; int m,len,pw[N]; int H[N],pos; struct node { int id,hash…

题目传送门 题意:训练指南P225 分析:二分寻找长度,用hash值来比较长度为L的字串是否相等. #include <bits/stdc++.h> using namespace std; typedef unsigned long long ull; const int N = 4e4 + 5; const int x = 123; ull H[N], _hash[N], xp[N]; int rk[N]; char str[N]; int m; void get_hash(char *s…

However, all efforts to decode their messages have failed so far because, as luck would have it, they have stumbled upon a race of stuttering aliens! Her team has found out that, in every long enough message, the most important words appear repeated…

Stammering Aliens Time Limit: 2000MS   Memory Limit: 65536K       Description Dr. Ellie Arroway has established contact with an extraterrestrial civilization. However, all efforts to decode their messages have failed so far because, as luck would hav…

后缀数组的倍增算法(Prefix Doubling) 文本内容除特殊注明外,均在知识共享署名-非商业性使用-相同方式共享 3.0协议下提供,附加条款亦可能应用. 最近在自学习BWT算法(Burrows-Wheeler transform),其中涉及到对字符串循环移位求编码.直观的办法就是模拟,使用O(n3)的时间求出BWT编码.经过简单的简化后也要O(n2logn)的时间,显然当字符串长度很大时这种方法的效率很低. 由于循环移位的结果类似后缀(二者有所不同,所以在字符串结尾添加了一个字典序严格小…

4199: [Noi2015]品酒大会 UOJ:http://uoj.ac/problem/131 一年一度的“幻影阁夏日品酒大会”隆重开幕了.大会包含品尝和趣味挑战两个环节,分别向优胜者颁发“首席品酒家”和“首席猎手”两个奖项,吸引了众多品酒师参加. 在大会的晚餐上,调酒师 Rainbow 调制了 nn 杯鸡尾酒.这 nn 杯鸡尾酒排成一行,其中第 ii 杯酒 (1≤i≤n1≤i≤n) 被贴上了一个标签 sisi,每个标签都是 2626 个小写英文字母之一.设 Str(l,r)Str(l,r)…