题目   点这里看题目. 分析   设前缀和\(s_r=\sum_{i=1}^r [S_i='1']\)   考虑满足要求的子串\((l,r]\)的要求: \[\exists k\in N_+, r-l=k(s_r-s_l) \]   单独计算并不好算,考虑一个分块的优化.设置阈值\(T\).   对于\(1\le k\le T\)的\(k\),对要求进行变形: \[r-l=k(s_r-s_l)\Rightarrow ks_r-r=ks_l-l \]   设\(f(i,k)=ks_i-i\),那…

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 "…