题面 给一个长度为 2 N 2N 2N 的序列 A A A,定义一个长度为 2 N 2N 2N 的合法括号序列的 得分(score) 为: 对于每对配对的括号 i , j i,j i,j, ∣ A i − A j ∣ |A_i-A_j| ∣Ai​−Aj​∣ 的和. 输出得分最高的任意一个合法括号序列. 1 ≤ N ≤ 2 ⋅ 1 0 5 1\leq N\leq 2\cdot10^5 1≤N≤2⋅105. 题解 我们先想一个相关的问题: 在数轴上从左到右存在 2 N 2N 2N 个点(可重合),点…

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 characters…

题目链接: http://codeforces.com/contest/670/problem/E 题解: 用STL的list和stack模拟的,没想到跑的还挺快. 代码: #include<iostream> #include<cstdio> #include<cstring> #include<map> #include<list> #include<stack> using namespace std; + ; const in…

题意:计算Bestcoder四题的得分. 思路:直接模拟,4项分数直接计算后输出.注意不要低于百分之40的分. //#include <bits/stdc++.h> #include <iostream> #include <cstdio> #define LL long long using namespace std; ; int a[N]; int b[N]; int cal() { ; ans=(/*(-a[])-b[]* >*/*(-a[])-b[]*:…

题意:给定一个正则括号序列 s ,让你在当中选择一个长度正好为 t 的子串,使得 t 恰好也是一个正则括号序列 思路:用栈模拟 #include<cstdio> #include<cstring> #include<string> #include<cmath> #include<iostream> #include<algorithm> #include<map> #include<set> #include…

题意:给你一串括号,每次仅可以修改一个位置,问有多少位置仅修改一次后所有括号合法. 题解:我们用栈来将这串括号进行匹配,每成功匹配一对就将它们消去,因为题目要求仅修改一处使得所有括号合法,所以栈中最后一定会有两个括号剩余,并且这两个括号要么是\(((\)要么是\())\),\()(\)是无论如何都不合法的,对于\())\),我们去找它左边的\()\)的个数贡献给答案(因为每次修改可以使[\((++\),\()--\)],所以栈中剩余的\())\)就没有了),对于\(((\)的情况也是一样的,我们…

题目地址: 选题为入门的Codeforce div2/div1的C题和D题. 题解: A:CF思维联系–CodeForces -214C (拓扑排序+思维+贪心) B:CF–思维练习-- CodeForces - 215C - Crosses(思维题) C:CF–思维练习–CodeForces - 216C - Hiring Staff (思维+模拟) D:CF思维联系–CodeForces-217C C. Formurosa(这题鸽了) E:CF思维联系–CodeForces - 218C E…

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…

ACM思维题训练集合 A bracket sequence is a string containing only characters "(" and ")". A regular bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters "1" and &…

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…