给一个原串,以及那些字符是坏的,现在问你可以从原串中取出多少个不同子串,使得其所含的坏字符的个数不超过一个定数. 这个题目网上有各种各样的解法.如hash,tire. 我说一下我的解法. 解法一:后缀自动机dp.f[][]保存到达某个状态,前面已经有的坏字符的个数的时候的字符串数量.这样按照拓扑序列一直递推下去就可以了.时间复杂度为O(N2). 解法二:后缀自动机,预处理.对于字符串,每个位置保存它可以最前走到那个位置.然后,在自动机上增加信息,保存位置.然后直接按照距离判断就可以了.对于每个节…

Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz", so s will look like this: "...zabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd....". Now we have another string p. Your job is to find…

Consider the string s to be the infinite wraparound string of "abcdefghijklmnopqrstuvwxyz", so s will look like this: "...zabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd....". Now we have another string p. Your job is to find…

Description String analysis often arises in applications from biology and chemistry, such as the study of DNA and protein molecules. One interesting problem is to find how many substrings are repeated (at least twice) in a long string. In this proble…

Codeforces Round #258 (Div. 2) Count Good Substrings D. Count Good Substrings time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output We call a string good, if after merging all the consecutive eq…

题目 Source http://acm.hust.edu.cn/vjudge/problem/19225 Description The Hamming distance between two strings of the same length is defined as the number of positions at which the corresponding characters are different. For example, the Hamming distance…

Description Given a string, we need to find the total number of its distinct substrings. Input T- number of test cases. T<=20; Each test case consists of one string, whose length is <= 50000 Output For each test case output one number saying the num…

题意:由a和b构成的字符串,如果压缩后变成回文串就是Good字符串.问一个字符串有几个长度为偶数和奇数的Good字串. 分析:可知,因为只有a,b两个字母,所以压缩后肯定为..ababab..这种形式,所以是good substrings,那么首尾字符肯定相同,于是就好搞了. 用:odd[0],odd[1]分别记录奇数位置上出现的a和b的个数,even[0],even[1]分别记录偶数位置上的a,b个数. 那么到一个奇数点时,奇数长度的子串个数应该加上奇数位置的该字符的个数,偶数长度的应该加上偶…

694. Distinct Substrings Problem code: DISUBSTR   Given a string, we need to find the total number of its distinct substrings. Input T- number of test cases. T<=20;Each test case consists of one string, whose length is <= 1000 Output For each test c…

A. Two Substrings Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/A Description You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings "AB" and "…