C. Sereja and Brackets time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Sereja has a bracket sequence s1, s2, ..., sn, or, in other words, a string s of length n, consisting of characters "(…

题目链接:http://codeforces.com/contest/381/problem/E  E. Sereja and Brackets time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Sereja has a bracket sequence s1, s2, ..., sn, or, in other words, a…

题目链接 给一个括号序列, 两种操作. 一种将某个位置的括号变反(左变右, 右变左), 第二种是询问这个括号序列是否合法. 线段树, 我们开两个数组lf, rg. 表示某个区间里面, 右边的左括号个数, 和左边的右括号个数. ))(( 这个序列lf和rg就都是2. (())这样的话都是0. 如果合法, 那么lf, rg都等于0. #include <iostream> #include <vector> #include <cstdio> #include <cs…

Sereja has a bracket sequence s1, s2, ..., sn, or, in other words, a string s of length n, consisting of characters "(" and ")". Sereja needs to answer m queries, each of them is described by two integers li, ri(1 ≤ li ≤ ri ≤ n). The a…

题意:给出一个括号序列,要求维护两种操作: 1.将第x位上的括号取反 2.查询当前整个括号序列是否匹配 n<=3e4 思路:线段树维护区间内没有匹配的左右括号数量 pushup时t[p].r=t[rs].r+t[ls].r-min(t[ls].l,t[rs].r) 不知道这个式子怎么推出来的,但在四种情况下它都成立 #include<cstdio> #include<cstring> #include<string> #include<cmath> #…

Sereja and Brackets 题目链接: CodeForces - 380C Sereja has a bracket sequence s1, s2, ..., *s**n, or, in other words, a string s* of length n, consisting of characters "(" and ")". Sereja needs to answer m queries, each of them is describe…

链接: http://acm.hust.edu.cn/vjudge/contest/view.action?cid=87813#problem/J Description Daniel has a string s, consisting of lowercase English letters and period signs (characters '.'). Let's define the operation of replacement as the following sequenc…

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…

E. Editor The development of a text editor is a hard problem. You need to implement an extra module for brackets coloring in text. Your editor consists of a line with infinite length and cursor, which points to the current character. Please note that…

链接: https://codeforces.com/contest/1263/problem/E 题意: The development of a text editor is a hard problem. You need to implement an extra module for brackets coloring in text. Your editor consists of a line with infinite length and cursor, which point…