题意:最多有多少括号匹配 思路:区间dp,模板dp,区间合并. 对于a[j]来说: 刚開始的时候,转移方程为dp[i][j]=max(dp[i][j-1],dp[i][k-1]+dp[k][j-1]+2), a[k]与a[j] 匹配,结果一组数据出错 ([]]) 检查的时候发现dp[2][3]==2,对,dp[2][4]=4,错了,简单模拟了一下发现,dp[2][4]=dp[2][1]+dp[2][3]+2==4,错了 此时2与4已经匹配,2与3已经无法再匹配. 故转移方程改为dp[i][j]=…

题目链接:http://poj.org/problem?id=2955 题目大意:给你一串字符串,求最大的括号匹配数. 解题思路: 设dp[i][j]是[i,j]的最大括号匹配对数. 则得到状态转移方程: if(str[i]=='('&&str[j]==')'||(str[i]=='['&&str[j]==']')){ dp[i][j]=dp[i+1][j-1]+1; }dp[i][j]=min(dp[i][j],dp[i][k]+dp[k+1][j]) ,(i<=k…

Brackets We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regular brackets sequence, if s is a regular brackets sequence, then (s) and [s] are regular brackets sequences, and if a and b are regular…

Brackets Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6033   Accepted: 3220 Description We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regular brackets sequence, if s is a regular…

Brackets Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5424   Accepted: 2909 Description We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regular brackets sequence, if s is a regular…

描述给你一个字符串,里面只包含"(",")","[","]"四种符号,请问你需要至少添加多少个括号才能使这些括号匹配起来.如:[]是匹配的([])[]是匹配的((]是不匹配的([)]是不匹配的   输入 第一行输入一个正整数N,表示测试数据组数(N<=10)每组测试数据都只有一行,是一个字符串S,S中只包含以上所说的四种字符,S的长度不超过100 输出 对于每组测试数据都输出一个正整数,表示最少需要添加的括号的数量.每组…

Description Let us define a regular brackets sequence in the following way: 1. Empty sequence is a regular sequence. 2. If S is a regular sequence, then (S) and [S] are both regular sequences. 3. If A and B are regular sequences, then AB is a regular…

http://acm.hust.edu.cn/vjudge/contest/view.action?cid=105116#problem/E 题意:添加最少的括号,让每个括号都能匹配并输出 分析:dp[i][j]表示第i个到第j个需要添加的最少的括号,pos[i][j] = k;表示i到j间第k个需要加括号: 如果str[i]和str[j]匹配,那么dp[i][j] = max(dp[i + 1][j - 1], dp[i][j]); 如果str[i]和str[j]不匹配,那么dp[i][j]…

解题关键:了解转移方程即可. 转移方程:$dp[l][r] = dp[l + 1][r - 1] + 2$ 若该区间左右端点成功匹配.然后对区间内的子区间取max即可. nyoj15:求需要添加的最少的括号数量,用总数减去$dp[0][s.size()-1]$即可. #include<cstdio> #include<cstring> #include<algorithm> #include<cstdlib> #include<cmath> #i…

题目:http://poj.org/problem?id=1141 转载:http://blog.csdn.net/lijiecsu/article/details/7589877 定义合法的括号序列如下: 1 空序列是一个合法的序列 2 如果S是合法的序列,则(S)和[S]也是合法的序列 3 如果A和B是合法的序列,则AB也是合法的序列 例如:下面的都是合法的括号序列 (),  [],  (()),  ([]),  ()[],  ()[()] 下面的都是非法的括号序列 (,  [,  ),  …