传送门 D. A and B and Interesting Substrings time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A and B are preparing themselves for programming contests. After several years of doing sports pro…

题意: 对于26个字母 每个字母分别有一个权值 给出一个字符串,找出有多少个满足条件的子串, 条件:1.第一个字母和最后一个相同,2.除了第一个和最后一个字母外,其他的权和为0 思路: 预处理出sum[i]:s[0~i]的和 开26个map<LL, LL>numV 分别表示 每个字母前缀和 的个数 例如处理到第i个元素,且numV[s[i]-'a'][sum[i]-v[s[i] - 'a']] (值为2) 表示在处理到的元素之前 以s[i]结尾的前缀和为sum[i]-v[s[i]-'a']的个…

D. A and B and Interesting Substrings time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A and B are preparing themselves for programming contests. After several years of doing sports program…

水 A. A and B and Chess /* 水题 */ #include <cstdio> #include <algorithm> #include <iostream> #include <cstring> #include <string> using namespace std; const int maxn = 1e6 + 10; int a[maxn]; int main(void) { //freopen ("A.…

C. A and B and Team Training time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output A and B are preparing themselves for programming contests. An important part of preparing for a competition is s…

B. A and B and Compilation Errors time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A and B are preparing themselves for programming contests. B loves to debug his code. But before he runs t…

A. A and B and Chess time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output A and B are preparing themselves for programming contests. To train their logical thinking and solve problems better, A…

A and B and Lecture Rooms time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A and B are preparing themselves for programming contests. The University where A and B study is a set of rooms co…

B. Alyona and a tree 题目连接: http://codeforces.com/contest/739/problem/B Description Alyona has a tree with n vertices. The root of the tree is the vertex 1. In each vertex Alyona wrote an positive integer, in the vertex i she wrote ai. Moreover, the g…

C. Weakness and Poorness Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/578/problem/C Description You are given a sequence of n integers a1, a2, ..., an. Determine a real number x such that the weakness of the sequence a1 -…