UVA10298 Power Strings hash+乘法逆元+一点点数学知识 我们用取余法算出主串的hash,然后从小到大枚举子串的长度 显然,如果若干个子串的复制的hash值之和等于主串的hash值,那么答案就得到了. 然后我们计算子串(设子串长度为 i )的hash值: hash=t*(+base^i+base^2i+...+base^(len-i)) 如果直接暴力求,那么显然会TLE 于是我们进行推导: 设: Si=+base^i+base^2i+...+base^(len-i) S=…

题目传送门 Power Strings 格式难调,题面就不放了. 一句话题意,求给定的若干字符串的最短循环节循环次数. 输入样例#1: abcd aaaa ababab . 输出样例#1: 1 4 3 就这样. 分析: 一道思路神奇的题目,需要深入理解$KMP$的$next$数组. 如果自己写几个字符串推一下就可以发现,一个由循环节构成的字符串,从第二个循环节开始$next$值是依次递增的,因为$next$数组的本质是表示$0\~i-1$的最长公共前缀后缀长度.也就不难想到,只要判断一下$nex…

Analysis 结论:设字符串长度为n,最长相同前后缀的长度为kmp[i],如n%(n-kmp[n])=0,则答案为n/(n-kmp[n]),否则为1. 如果循环节多于一个,以前n-kmp[n]个为循环节,是可以铺满整串的.而且因为kmp[n]是尽量大的,所以这样得到的循环节长度为所有可能情况中最小的,也就是我们所求的. 而如果n%(n-kmp[n])≠0,可以认为之前的循环节匹配仍然可以进行,但是最后一个循环节被强行割掉了一些. #include<iostream> #include<…

题目描述 PDF 输入输出格式 输入格式: 输出格式: 输入输出样例 输入样例#1: 复制 abcd aaaa ababab . 输出样例#1: 复制 1 4 3 题解 Luogu的题解 这里是对目前最高赞题解结论的证明. 结论:设字符串长度为$n$,最长相同前后缀的长度为$next[i]$, 如$n$%$(n-next[n])=0$,则答案为$n/(n-next[n])$,否则为$1$. 证明: 我们求$next$数组的时候,相当于每次把当前串这样对齐了一下↓ 而$next$求到$n$时,上面…

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…

F - Power Strings Time Limit:3000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 2406 Description Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = &…

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 = "…

Power Strings Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 41252   Accepted: 17152 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 = "…

E - Power Strings Time Limit:3000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 2406 Description Given two strings a and b we define a*b to be their concatenation. For example, if a = "abc" and b = &…

点击打开链接 Power Strings Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 27368   Accepted: 11454 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 =…