题意:就给出个字符串做*的定义.a^0 = "" (the empty string) and a^(n+1) = a*(a^n).    题目要求n的最大值. 思路: 化简上面的等式之后就知道是求a的n次方,也就是说求所给字符串的最大循环次数,想一想. 如果可以求出所给字符串的最小循环节, 那么是不是就可以求出它的最大循环次数了.   这是肯定的. 因为循环节最小. 循环次数也就最大 #include<iostream> #include<cstring> #…

连续重复子串问题 poj 2406 Power Strings http://poj.org/problem?id=2406 问一个串能否写成a^n次方这种形式. 虽然这题用kmp做比较合适,但是我们还是用后缀数组做一做,巩固后缀数组的能力. 对于一个串,如果能写出a^n这种形式,我们可以暴力枚举循环节长度L,那么后缀suffix(1)和suffix(1 + L)的LCP应该就是 lenstr - L.如果能满足,那就是,不能,就不是. 这题的话da算法还是超时,等我学了DC3再写上来. 其实这…

Power Strings Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 28859   Accepted: 12045 Description Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = "def" then a*b = "…

题目传送门 /* 题意:一个串有字串重复n次产生,求最大的n KMP:nex[]的性质应用,感觉对nex加深了理解 */ /************************************************ * Author :Running_Time * Created Time :2015-8-10 10:51:54 * File Name :POJ_2406.cpp ************************************************/ #incl…

http://poj.org/problem?id=2406 Power Strings Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 27003   Accepted: 11311 Description Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = &q…

Power Strings Time Limit: 3000MSMemory Limit: 65536K Total Submissions: 29663Accepted: 12387 Description Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = "def" then a*b = "abcdef…

Power Strings Problem's Link: http://poj.org/problem?id=2406 Mean: 给你一个字符串,让你求这个字符串最多能够被表示成最小循环节重复多少次得到. analyse: KMP之next数组的运用.裸的求最小循环节. Time complexity: O(N) Source code:  ;;      ;);      ) ;}/* */…

                                                                                                  Power Strings Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 38038   Accepted: 15740 Description Given two strings a and b we define a*b t…

Power Strings Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 30069   Accepted: 12553 Description Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = "def" then a*b = "…

题意:求最小循环节循环的次数. 题解:这个题其实可以直接用kmp去求最小循环节,然后在用总长度除以循环节.但是因为在练后缀数组,所以写的后缀数组版本.用倍增法会超时!!所以改用DC3法.对后缀数组还不是很理解,找了很多博客也没看懂到底有些数组到底记录的是啥,但他的实现过程很好理解,等我弄懂了再来给博客加注释吧. 先求出sa数组,height数组,rank数组(因为和c++库中某个东西重了所以写成rnk数组),数组一定要开3倍.接下来从小到大枚举循环节长度 i,如果长度i的子串刚好是重复了len/…