题目链接:https://codeforces.com/contest/670/problem/E 题意: 给出一个已经匹配的括号串,给出起始的光标位置(光标总是指向某个括号). 有如下操作: 1.往左移动一下光标: 2.往左移动一下光标: 3.删除当前光标指向的括号,以及和它匹配的那个括号,以及这两个括号之间的所有括号. 要求你给出在做完所有操作后的括号串. 题解: 数组模拟链表即可,每种操作都是 $O(1)$ 的时间复杂度. 另外可以参看:本题的对顶栈做法.本题的线段树做法. AC代码: #…

E. Correct Bracket Sequence Editor time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbrev…

题目链接:https://codeforces.com/contest/670/problem/E 题意: 给出一个已经匹配的括号串,给出起始的光标位置(光标总是指向某个括号). 有如下操作: 1.往左移动一下光标: 2.往左移动一下光标: 3.删除当前光标指向的括号,以及和它匹配的那个括号,以及这两个括号之间的所有括号. 要求你给出在做完所有操作后的括号串. 题解: 用线段树维护,每个括号是否存在,存在记为 $1$,被删掉了记为 $0$. 然后我们只需要实现:①区间求和.②区间赋值.③根据 $…

题目链接:https://codeforces.com/contest/670/problem/E 题意: 给出一个已经匹配的括号串,给出起始的光标位置(光标总是指向某个括号). 有如下操作: 1.往左移动一下光标: 2.往左移动一下光标: 3.删除当前光标指向的括号,以及和它匹配的那个括号,以及这两个括号之间的所有括号. 要求你给出在做完所有操作后的括号串. 题解: 用对顶栈进行模拟.由于删除是不可逆的,因此删除的总时间复杂度为 $O(n)$,因此所有 $m$ 次操作的总时间复杂度为 $O(n…

链表,模拟. 写一个双向链表模拟一下过程. #pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #include<vector> #include<map> #include<set> #include&…

题目链接:http://codeforces.com/contest/670/problem/E 给你n长度的括号字符,m个操作,光标初始位置是p,'D'操作表示删除当前光标所在的字符对应的括号字符以内的所有字符(比如'(()())'),'R'操作表示右移光标,'L'操作表示左移光标.删除操作后光标向右移,要是再向右移没有字符的话,那就停在最后的字符上了.问你最后的括号字符是怎么样的. 这题用链表写简单多了,直接模拟操作就行了,我用stl里的list. #include <bits/stdc++…

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…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbreviated as CBS). Note that a bracket sequ…

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 "…