后缀自动机(SAM) ：SPOJ LCS - Longest Common Substring

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后缀自动机(SAM) ：SPOJ LCS - Longest Common Substring

LCS - Longest Common Substring no tags A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at…

SPOJ LCS Longest Common Substring 和 LG3804 【模板】后缀自动机

Longest Common Substring 给两个串A和B,求这两个串的最长公共子串. no more than 250000 分析参照OI wiki. 给定两个字符串 S 和 T ,求出最长公共子串,公共子串定义为在 S 和 T 中都作为子串出现过的字符串 X . 我们为字符串 S 构造后缀自动机. 我们现在处理字符串 T ,对于每一个前缀都在 S 中寻找这个前缀的最长后缀.换句话说,对于每个字符串 T 中的位置,我们想要找到这个位置结束的 S 和 T 的最长公共子串的长度. 为…

SPOJ LCS Longest Common Substring（后缀自动机）题解

题意: 求两个串的最大$LCS$. 思路: 把第一个串建后缀自动机,第二个串跑后缀自动机,如果一个节点失配了,那么往父节点跑,期间更新答案即可. 代码: #include<set> #include<map> #include<cmath> #include<queue> #include<bitset> #include<string> #include<cstdio> #include<vector>…

SPOJ LCS - Longest Common Substring 字符串 SAM

原文链接http://www.cnblogs.com/zhouzhendong/p/8982392.html 题目传送门 - SPOJ LCS 题意求两个字符串的最长公共连续子串长度. 字符串长$\leq 250000$ 题解首先对于第一个字符串建一个$SAM$. 然后拿第二个串在$SAM$上面走一遍就好了. 具体地: 将第二个串的字符一个一个地按照顺序加入. 设当前状态为$now$,要加入字符$c$,当前匹配的字符串长度为$len$(答案自然是各种情况下$len$的最大值). 如果在$SA…

【SPOJ】Longest Common Substring II （后缀自动机）

[SPOJ]Longest Common Substring II (后缀自动机) 题面 Vjudge 题意:求若干个串的最长公共子串题解对于某一个串构建$SAM$ 每个串依次进行匹配同时记录$f[i]$表示走到了$i$节点能够匹配上的最长公共子串的长度当然,每个串的$f[i]$可以更新$f[i.parent]$ 所以需要拓扑排序对于每个串求出每个节点的最长匹配然后对他们取$min$,表示某个节点大家都能匹配的最长长度最后对于所有点的值都取个$max$…

【SPOJ】Longest Common Substring（后缀自动机）

[SPOJ]Longest Common Substring(后缀自动机) 题面 Vjudge 题意:求两个串的最长公共子串题解 $SA$的做法很简单不再赘述对于一个串构建$SAM$ 另外一个串在$SAM$上不断匹配最后计算答案就好了匹配方法: 如果$trans(s,c)$存在直接沿着$trans$走就行,同时$cnt++$ 否则沿着$parent$往上跳如果存在$trans(now,c),cnt=now.longest+1$ 否则,如果不存在可行的…

spoj 1811 LCS - Longest Common Substring (后缀自己主动机)

spoj 1811 LCS - Longest Common Substring 题意: 给出两个串S, T, 求最长公共子串. 限制: |S|, |T| <= 1e5 思路: dp O(n^2) 铁定超时后缀数组 O(nlog(n)) 在spoj上没试过,感觉也会被卡掉后缀自己主动机 O(n) 我们考虑用SAM读入字符串B; 令当前状态为s,同一时候最大匹配长度为len; 我们读入字符x.假设s有标号为x的边,那么s=trans(s,x),len = len+1; 否则我们找到s的第一个祖…

spoj1811 LCS - Longest Common Substring

地址:http://www.spoj.com/problems/LCS/ 题面: LCS - Longest Common Substring no tags A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecut…

【SPOJ】Longest Common Substring

[SPOJ]Longest Common Substring 求两个字符串的最长公共子串对一个串建好后缀自动机然后暴力跑一下废话讲一下怎么跑吧从第一个字符开始遍历,遍历不到了再沿着$parents$走看能否找到出路,走到某个点时,统计一下走过了多少点然后更新答案来说说这样做的正确性: 遍历是肯定的, SAM 从根节点出发的任意路径都表示一个子串沿着$parents$边往后走,保证贪心情况下维护最长公共子串寻找出路注意这里是统计走过了多少点更新答案,不能直接通过$len$…

【SP1811】LCS - Longest Common Substring

[SP1811]LCS - Longest Common Substring 题面洛谷题解建好后缀自动机后从初始状态沿着现在的边匹配, 如果失配则跳它的后缀链接,因为你跳后缀链接到达的$Endpos$集合中的串肯定是当前$Endpos$中的后缀,所以这么做是对的. 你感性理解一下,这样显然是最大的是吧... 具体实现看代码: 代码 #include <iostream> #include <cstdio> #include <cstdlib> #inclu…

【SPOJ】Longest Common Substring II

[SPOJ]Longest Common Substring II 多个字符串求最长公共子串还是将一个子串建SAM,其他字符串全部跑一边,记录每个点的最大贡献由于是所有串,要对每个点每个字符串跑完后去最小值才是每个点的最终贡献 #include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<algorithm…

SPOJ 1811. Longest Common Substring （LCS，两个字符串的最长公共子串，后缀自动机SAM）

1811. Longest Common Substring Problem code: LCS A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occur…

LCS - Longest Common Substring(spoj1811) (sam(后缀自动机)+LCS)

A string is finite sequence of characters over a non-empty finite set $\sum$. In this problem, $\sum$ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string. N…

SPOJ LCS2 - Longest Common Substring II 后缀自动机多个串的LCS

LCS2 - Longest Common Substring II no tags A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrence…

SPOJ 1812 Longest Common Substring II（后缀自动机）（LCS2）

A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string. Now your task i…

SPOJ1811 LCS - Longest Common Substring(后缀自动机)

A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string. Now your task i…

SPOJ LCS(Longest Common Substring-后缀自动机-结点的Parent包含关系)

1811. Longest Common Substring Problem code: LCS A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occur…

【刷题】SPOJ 1811 LCS - Longest Common Substring

A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string. Now your task i…

SPOJ 1811 LCS - Longest Common Substring

思路和SPOJ 1812 LCS2 - Longest Common Substring II一个思路,改成两个串就有双倍经验了代码 #include <cstdio> #include <algorithm> #include <cstring> using namespace std; int maxlen[502000],suflink[502000],barrel[502000],trans[502000][26],Nodecnt,ranks[502000]…

SPOJ LCS2 - Longest Common Substring II

LCS2 - Longest Common Substring II A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at leas…

SPOJ 1812 Longest Common Substring II

A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ is the set of lowercase letters. Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string. Now your task i…

SPOJ 1811LCS Longest Common Substring

后缀自己主动机裸题.... Longest Common Substring Time Limit: 2000MS Memory Limit: Unknown 64bit IO Format: %lld & %llu [Submit] [Go Back] [Status] Description A string is finite sequence of characters over a non-empty finite set Σ. In this problem, Σ…

SPOJ 1811 Longest Common Substring (后缀自动机第一题，求两个串的最长公共子串)

题目大意: 给出两个长度小于等于25W的字符串,求它们的最长公共子串. 题目链接:http://www.spoj.com/problems/LCS/ 算法讨论: 二分+哈希, 后缀数组, 后缀自动机. 随意做.这里面只写一下我对后缀自动机做法的理解. 首先,我们假设两个串分别为A串和B串,我们先对建立出A串的后缀自动机,然后对于B串的每一位,我们进行如下的操作:首先从第1位开始,Parent树上的位置在root,那么对于每一次操作,如果当前结点的字符可以匹配当前B串中所考虑到的字符,那么自然就l…

SPOJ 1812 Longest Common Substring II（后缀自动机）

[题目链接] http://www.spoj.com/problems/LCS2/ [题目大意] 求n个串的最长公共子串 [题解] 对一个串建立后缀自动机,剩余的串在上面跑,保存匹配每个状态的最小值, 取最小值中的最大值即可.由于跑的地方只记录了匹配结尾的状态, 所以还需要更新parent树上的状态,既然匹配到了子节点, 那么parent树链上的值就都能够取到l, 一开始给每个不同状态按照l从小到大分配储存地址, 这样,我们就可以从匹配长度最长的开始更新parent树的情况. [代码] #inc…

SPOJ - LCS2 Longest Common Substring II（后缀自动机）题解

题意: 求$n$个串的最大$LCS$. 思路: 把第一个串建后缀自动机,然后枚举所有串.对于每个串,求出这个串在$i$节点的最大匹配为$temp[i]$(当前串在这个节点最多取多少),然后我们求出最终所有串在$i$节点的匹配最小值$mn[i]$(即为所有串在$i$节点都能取到多少),答案即为$max\{min[i]\}$. 但是我们能发现,如果我们更新了$temp[i]$,那么其实$fa[i]$的$temp[fa[i]]$也应该要更新,因为父节点是我的…