D. Least Cost Bracket Sequence 题目连接: http://www.codeforces.com/contest/3/problem/D Description 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…

Least Cost Bracket Sequence(贪心) Describe 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, sequenc…

Least Cost Bracket Sequence CodeForces - 3D 题目描述 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,…

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…

题目 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 "(())()", "()"…

题目大意: 这是一个规则的字符括号序列.一个括号序列是规则的,那么在序列里面插入‘+’ 和 ‘1’ 会得到一个正确的数学表达式. 合法:(())(), (),(()(())) 不合法:)(,((),(()))( 给你一个字符序列,里面包含‘(’,‘)’ 和‘?’ 我们需要替换所有的‘?’,替换为“(” 和 ‘)’,在所有可能中找到花费最小的. 输入数据: 首先是一个字符串. 然后是m行,每行两个数字ai, 和 bi. 分别代表将第i个问号换为'(' 和‘)’ 的花费. 如果不能得到匹配的串则输出…

题目链接 给一个字符串, 由( ) 以及? 组成, 将?换成( 或者 ) 组成合法的括号序列, 每一个?换成( 或者 ) 的代价都不相同, 问你最小代价是多少, 如果不能满足输出-1. 弄一个变量num, 如果是( 那么num++,如果是)那么num--. 如果碰到?, 那么先将这个地方弄成), 然后把make_pair(b-a, i)加到一个队列里面.a是换成左括号的值, b是换成右括号的值, i是这个位置的坐标. 如果遇到num小于0的情况, 那么就将队首元素取出, 将这个位置换成左括号.…

Codeforces 3 D 题意:有一个括号序列,其中一些位置是问号,把第\(i\)个问号改成(需要\(a_i\)的代价,把它改成)需要\(b_i\)的代价. 问使得这个括号序列成立所需要的最小代价. 思路1: 这个是正统的贪心. 首先我们假设所有的位置上都是),那么我们在从左向右扫描的途中会发现一些问题. 比如:我们原来的序列是(??),现在假设成了())),那么在第三个字符处就会发现我们的打开的左括号数量为\(-1\),这是肯定不行的,所以我们必须把第二个字符或者第三个字符改成左括号以把左…

传送门 Description 给一个序列,序列里面会有左括号.问号.右括号.对于一个\(?\)而言,可以将其替换为一个\((\),也可以替换成一个\()\),但是都有相应的代价.问:如何替换使得代价最小.前提是替换之后的序列中,括号是匹配的.如果不能替换为一个括号匹配的序列则输出-1. Input 第一行是序列,序列长度不超过\(5~\times10^4\),下面m(m是\(m\)的数量)行有每行\(2\)个数据,第一个是\((\)的代价,第2个是\()\)的代价 Output 第一行输出最小…

哎,昨天一直在赶课设..没有写 最近听了一些人的建议,停止高级算法的学习,开始刷cf. 目前打算就是白天懒得背电脑的话,系统刷一遍蓝书紫书白书之类的(一直没系统刷过),回宿舍再上机吧. https://www.luogu.org/problem/CF3D 题意:就是给你一个由 '(' , ')' , '?'组成的字符串,可以把'?'变成'('或')',但需要一定的代价,问使得括号匹配前提下的最小代价. 做法:贪心真的是个神奇的东东..可以这么做,先从左扫到右,遇到'('就mark++,否则mar…

Description 给出一个括号序列,中间有一些问号,将第i个问号换成左括号代价是a[i],换成右括号代价是b[i],问如果用最少的代价将这个括号序列变成一个合法的括号序列 Input 第一行一个括号序列,假设其中有m个问号,则之后输入m行,每行两个整数a[i]和b[i]表示把第i个问号换成左括号或右括号的代价(括号序列长度不超过5e4,1<=a[i],b[i]<=1e6) Output 如果不存在一种合理的替换方案使得该序列变成一个合法的括号序列则输出-1,否则输出最小代价和替换后的合法…

题目链接 题意: 给你一个含有(,),?的序列,每个?变成(或)有一定的花费,问变成课匹配的括号的最小花费. 分析: 首先如果能变成匹配的,那么就有右括号的个数始终不多于左括号且左右括号数量相等,那就好办了,从头到尾跑一次就可以了,然后所有?变成),如果右括号多了,找一个变成左括号,当然一次最多变一个,然后用一个优先队列维护就好了. 代码: #include <cstdio> #include <cstring> #include <queue> using names…

题目大意 洛谷链接 给一个序列,序列里面会有左括号.问号.右括号.对于一个?而言,可以将其替换为一个(,也可以替换成一个),但是都有相应的代价.问:如何替换使得代价最小.前提是替换之后的序列中,括号是匹配的.如果不能替换为一个括号匹配的序列则输出\(-1\). 输入格式 第一行是序列,序列长度不超过\(5×10^4\),下面\(m\)(\(m\)是?的数量)行有每行2个数据,第一个是(的代价,第二个是)的代价. 输出格式 第一行打印代价,第二行打印替换后的序列.不行输出\(-1\). 数据范围…

                                    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…

[#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 "(", ")"…

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…

C. Replace To Make Regular Bracket Sequence 题目连接: http://www.codeforces.com/contest/612/problem/C Description You are given string s consists of opening and closing brackets of four kinds <>, {}, [], (). There are two types of brackets: opening and…

C. Longest Regular Bracket Sequence Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/problemset/problem/5/C Description This is yet another problem dealing with regular bracket sequences. We should remind you that a bracket sequence…

There is a sequence of brackets, which supports two kinds of operations. we can choose a interval [l,r], and set all the elements range in this interval to left bracket or right bracket. we can reverse a interval, which means that for all the element…

Replace To Make Regular Bracket Sequence You are given string s consists of opening and closing brackets of four kinds <>, {}, [], (). There are two types of brackets: opening and closing. You can replace any bracket by another of the same type. For…

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…

You are given string s consists of opening and closing brackets of four kinds <>, {}, [], (). There are two types of brackets: opening and closing. You can replace any bracket by another of the same type. For example, you can replace < by the bra…

C. Replace To Make Regular Bracket Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are given string s consists of opening and closing brackets of four kinds <>, {}, [], (). Th…

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…

(CodeForces - 5C)Longest Regular Bracket Sequence time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output This is yet another problem dealing with regular bracket sequences. We should remind you t…

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 "…

题目传送门 /* 题意:求最长括号匹配的长度和它的个数 贪心+stack:用栈存放最近的左括号的位置,若是有右括号匹配,则记录它们的长度,更新最大值,可以在O (n)解决 详细解释:http://blog.csdn.net/taoxin52/article/details/26012167 */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmath> #includ…

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…

Almost Regular Bracket Sequence CodeForces - 1095E You are given a bracket sequence ss consisting of nn opening '(' and closing ')' brackets. A regular bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expressio…

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;…