[#138 div 1 A. Bracket Sequence] [原题] A. Bracket Sequence time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A bracket sequence is a string, containing only characters "(", ")"…

ACM思维题训练集合 A bracket sequence is a string, containing only characters "(", ")", "[" and "]". A correct bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting…

题目 传送门:QWQ 分析 洛谷题解里有一位大佬讲的很好. 就是先用栈预处理出可以匹配的左右括号在数组中设为1 其他为0 最后求一下最长连续1的数量. 代码 #include <bits/stdc++.h> using namespace std; ; char s[maxn]; int vis[maxn], Stack[maxn], top; int main(){ scanf(); ); ;i<=n;i++){ if(s[i]=='('){ Stack[++top]=i; } els…

E. Correct Bracket Sequence Editor 题目连接: http://www.codeforces.com/contest/670/problem/E Description Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbreviated as CBS). Note that a bracket sequence…

E. Correct Bracket Sequence Editor   Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbreviated as CBS). Note that a bracket sequence is correct if it is possible to get a correct mathematical expre…

传送门 题意: 给你一个只包含 '(' 和 ')' 的长度为 n 字符序列s: 给出一个操作:将第 i 个位置的字符反转('(' ')' 互换): 问有多少位置反转后,可以使得字符串 s 变为"Regular Bracket Sequence": 输出满足条件的位置的个数: 题解: 令 '(' = 1 , ')' = -1: 定义 sum[i]:括号序列的前缀和: 一个合法的括号匹配串的充要条件是: [1] 对于任何 i,sum[i] ≥ 0: [2] sum[n]=0: int n;…

题目地址:CF1095E Almost Regular Bracket Sequence 真的是尬,Div.3都没AK,难受QWQ 就死在这道水题上(水题都切不了,我太菜了) 看了题解,发现题解有错,不过还是看懂了QAQ 其实是一道好题 (话说CF的题有不好的么(雾 难在预处理 预处理两个数组: 前缀和:若 \(s_i\) 为 \((\) , \(s1_i=s1_{i-1}+1\) ,反之同理: 后缀和:若 \(s_i\) 为 \()\) , \(s2_i=s2_{i+1}+1\) ,反之亦同理…

This is yet another problem on regular bracket sequences. A bracket sequence is called regular, if by inserting "+" and "1" into it we get a correct mathematical expression. For example, sequences "(())()", "()" and…

Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbreviated as CBS). Note that a bracket sequence is correct if it is possible to get a correct mathematical expression by adding "+"-s and "…

                                    Bracket Sequence Time Limit: 3000MS   Memory Limit: 65536KB   64bit IO Format: %lld & %llu [Submit]   [Go Back]   [Status] Description There is a sequence of brackets, which supports two kinds of operations.1. we c…