CF1598F.RBS
提高+/省选-
通过率:0%
时间限制:3.00s
内存限制:512MB
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题目描述
A bracket sequence is a string containing only characters "(" and ")". A regular bracket sequence (or, shortly, an RBS) is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters "1" and "+" between the original characters of the sequence. For example:
- bracket sequences "()()" and "(())" are regular (the resulting expressions are: "(1)+(1)" and "((1+1)+1)");
- bracket sequences ")(", "(" and ")" are not.
Let's denote the concatenation of two strings x and y as x+y. For example, "()()" + ")(" = "()())(".
You are given n bracket sequences s1,s2,…,sn. You can rearrange them in any order (you can rearrange only the strings themselves, but not the characters in them).
Your task is to rearrange the strings in such a way that the string s1+s2+⋯+sn has as many non-empty prefixes that are RBS as possible.
括号序列是指仅由字符 ( 和 ) 组成的字符串。正则括号序列(简称 RBS)是指可以通过在原序列的字符之间插入字符 1 和 +,从而将其转化为合法算术表达式的括号序列。例如:
- 括号序列
"()()"和"(())"是正则的(得到的表达式分别为:"(1)+(1)"和"((1+1)+1)"); - 括号序列
")(","("和")"则不是。
我们用 x+y 表示两个字符串 x 和 y 的拼接。例如,"()()" + ")(" = "()())("。
给定 n 个括号序列 s1,s2,…,sn。你可以以任意顺序重新排列这些字符串(只能重新排列字符串本身,不能改变每个字符串内部字符的顺序)。
你的任务是将这些字符串重新排列,使得拼接后的字符串 s1+s2+⋯+sn 中,尽可能多地包含非空的、且为 RBS 的前缀。
输入格式
The first line contains a single integer n (1≤n≤20).
Then n lines follow, the i-th of them contains si — a bracket sequence (a string consisting of characters "(" and/or ")". All sequences si are non-empty, their total length does not exceed 4⋅105.
第一行包含一个整数 n(1≤n≤20)。
接下来有 n 行,其中第 i 行包含字符串 si —— 一个括号序列(由字符 "(" 和/或 ")" 组成的字符串)。所有序列 si 均非空,且它们的总长度不超过 4⋅105。
输出格式
Print one integer — the maximum number of non-empty prefixes that are RBS for the string s1+s2+⋯+sn, if the strings s1,s2,…,sn can be rearranged arbitrarily.
输出一个整数——字符串 s1+s2+⋯+sn 的非空前缀中,合法括号序列(RBS)的最大可能数量,其中字符串 s1,s2,…,sn 可以以任意顺序重新排列。
输入输出样例
输入#1
2 ( )
输出#1
1
输入#2
4 ()()()) ( ( )
输出#2
4
输入#3
1 (())
输出#3
1
输入#4
1 )(()
输出#4
0
说明/提示
In the first example, you can concatenate the strings as follows: "(" + ")" = "()", the resulting string will have one prefix, that is an RBS: "()".
In the second example, you can concatenate the strings as follows: "(" + ")" + "()()())" + "(" = "()()()())(", the resulting string will have four prefixes that are RBS: "()", "()()", "()()()", "()()()()".
The third and the fourth examples contain only one string each, so the order is fixed.
在第一个例子中,你可以按如下方式连接字符串:"(" + ")" = "()",所得字符串将有一个前缀是正则括号序列(RBS):"()"。
在第二个例子中,你可以按如下方式连接字符串:"(" + ")" + "()()())" + "(" = "()()()())(",所得字符串将有四个前缀是正则括号序列(RBS):"()"、"()()"、"()()()"、"()()()()"。
第三和第四个例子中各自仅包含一个字符串,因此顺序是固定的。
输入解题思路,AI测评打分。不知道怎么写?