求一个括号的最大匹配数,这个题可以和UVa 1626比较着看. 注意题目背景一样,但是所求不一样. 回到这道题上来,设d(i, j)表示子序列Si ~ Sj的字符串中最大匹配数,如果Si 与 Sj能配对,d(i, j) = d(i+1, j-1) 然后要枚举中间点k,d(i, j) = max{ d(i, k) + d(k+1, j) } #include <iostream> #include <cstdio> #include <cstring> #include…

第一道自己做出来的区间dp题,兴奋ing,虽然说这题并不难. 从后向前考虑: 状态转移方程:dp[i][j]=dp[i+1][j](i<=j<len); dp[i][j]=Max(dp[i][j],dp[i+1][k-1]+dp[k+1][j]+1),(a[i]==a[j]&&i<len,j<len,k<len); #include<stdio.h> #include<string.h> #define N 300 int dp[N][…

题目链接: http://poj.org/problem?id=2955 题目大意:括号匹配.对称的括号匹配数量+2.问最大匹配数. 解题思路: 看起来像个区间问题. DP边界:无.区间间隔为0时,默认为memset为0即可. 对于dp[i][j],如果i和j匹配,不难有dp[i][j]=dp[i+1][j-1]+2. 然后枚举不属于两端的中点, dp[i][j]=max(dp[i][j],dp[i][k]+dp[k][j]),合并两个区间的结果. #include "cstdio"…

Brackets Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 14226 Accepted: 7476 Description We give the following inductive definition of a "regular brackets" sequence: the empty sequence is a regular brackets sequence, if s is a regula…

Cheapest Palindrome Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 7869   Accepted: 3816 Description Keeping track of all the cows can be a tricky task so Farmer John has installed a system to automate it. He has installed on each cow a…

题目链接: http://poj.org/problem?id=1651 题目大意:加分取牌.如果一张牌左右有牌则可以取出,分数为左牌*中牌*右牌.这样最后肯定还剩2张牌.求一个取牌顺序,使得加分最少. 解题思路: 矩阵链乘的变种题. 假设有10.20.30.40.50五张牌. 如果我想要最后取30,则应该先取20.40,这样就还剩10.30.50三张牌了. 不难发现取20是dp[i][k]部分,取40是dp[k][j]部分,最后剩下的就是i.k.j三张牌. DP边界:无 因为是算加分,区间间隔…

Brackets Sequence Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 30383   Accepted: 8712   Special Judge Description Let us define a regular brackets sequence in the following way: 1. Empty sequence is a regular sequence. 2. If S is a re…

给一组小括号与中括号的序列,加入最少的字符,使该序列变为合法序列,输出该合法序列. dp[a][b]记录a-b区间内的最小值, mark[a][b]记录该区间的最小值怎样得到. #include "stdio.h" #include "string.h" int inf=99999999; char str[110]; int dp[110][110],mark[110][110]; void pri(int l,int r) { if (l>r) retur…

Blocks Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 5035   Accepted: 2065 Description Some of you may have played a game called 'Blocks'. There are n blocks in a row, each box has a color. Here is an example: Gold, Silver, Silver, Sil…

此题可以转化为最优矩阵链乘的形式,d(i, j)表示区间[i, j]所能得到的最小权值. 枚举最后一个拿走的数a[k],状态转移方程为d(i, j) = min{ d(i, k) + d(k, j) + a[i] * a[k] * a[j] } #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> using namespace std; + ; const…

题意: 思路: f[i][j][1]表示从i到j的区间全都吃完了 现在在j点 变质期最小是多少 f[i][j][0]表示从i到j的区间全都吃完了 现在在i点 变质期最小是多少 f[i][j][0]=min(f[i+1][j][0]+(s[i+1]-s[i])(n-j+i),f[i+1][j][1]+(s[j]-s[i])(n-j+i)); f[i][j][1]=min(f[i][j-1][1]+(s[j]-s[j-1])(n-j+i),f[i][j-1][0]+(s[j]-s[i])(n-j+i…

http://poj.org/problem?id=2955 题意:给出一串字符,求括号匹配的数最多是多少. 思路:区间DP. 对于每个枚举的区间边界,如果两边可以配对成括号,那么dp[i][j] = dp[i+1][j-1] + 2,表示由上一个状态加上当前的贡献. 然后和普通的区间合并一样去更新. #include <cstring> #include <cstdio> #include <iostream> #include <string> usin…

Brackets My Tags (Edit) Source : Stanford ACM Programming Contest 2004 Time limit : 1 sec Memory limit : 32 M Submitted : 188, Accepted : 113 5.1 Description We give the following inductive definition of a "regular brackets" sequence: • the empt…

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…

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 sequence, then (s) and [s] are regular brackets sequences, and if a and b are regul…

传送门 https://www.cnblogs.com/violet-acmer/p/9852294.html 题意: 给你一个只由 '(' , ')' , '[' , ']' 组成的字符串s[ ],求最大匹配? 题解: 定义dp[ i ][ j ] : 从第i个字符到第j个字符的最大匹配. 步骤: (1) : 如果s[ i ] 与 s[ j ]匹配,那么dp[ i ][ j ] =  2+dp[ i+1 ][ j-1 ];反之,dp[ i ][ j ] = 0; (2) : 接下来,从 i 到…

题意: 给出一个字符串,其中仅仅含 “ ( ) [ ] ” 这4钟符号,问最长的合法符号序列有多长?(必须合法的配对,不能混搭) 思路: 区间DP的常规问题吧,还是枚举区间[i->j]再枚举其中第k个与第i个来配对,如果配对了就+2这样子. //#include <bits/stdc++.h> #include <iostream> #include <cstdio> #include <cstring> #include <cmath>…

题目: 给出一个有括号的字符串,问这个字符串中能匹配的最长的子串的长度. 思路: 区间DP,首先枚举区间长度,然后在每一个长度中通过枚举这个区间的分割点来更新这个区间的最优解.还是做的少. 代码: //#include <bits/stdc++.h> #include <cstdio> #include <cstring> #include <iostream> #define MAX 1000000000 #define FRE() freopen(&qu…

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]=…

Brackets Sequence Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 29520   Accepted: 8406   Special Judge Description Let us define a regular brackets sequence in the following way: 1. Empty sequence is a regular sequence. 2. If S is a re…

POJ 2995 Brackets 区间DP 题意 大意:给你一个字符串,询问这个字符串满足要求的有多少,()和[]都是一个匹配.需要注意的是这里的匹配规则. 解题思路 区间DP,开始自己没想到是区间DP,以为就是用栈进行模拟呢,可是发现就是不大对,后来想到是不是使用DP,但是开始的时候自己没有推出递推关系,后来实在想不出来看的题解,才知道是区间DP,仔细一想确实是啊. 下面就是状态转移方程: \[ \begin{cases}dp[i][j] &=& dp[i+1][j-1]+if(str…

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…

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 sequence, then (s) and [s] are regular brackets sequences, and if a and b are regul…

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…

//poj 2955 //sep9 #include <iostream> using namespace std; char s[128]; int dp[128][128]; int n; int rec(int l,int r) { if(dp[l][r]!=-1) return dp[l][r]; if(l==r) return dp[l][r]=0; if(l+1==r){ if(s[l]=='('&&s[r]==')') return dp[l][r]=2; if(…

题目链接:http://poj.org/problem?id=2955 题意:给定字符串 求括号匹配最多时的子串长度. 区间dp,状态转移方程: dp[i][j]=max ( dp[i][j] , 2+dp[i+1][k-1]+dp[k+1][j] ); 代码: #include<iostream> #include<cstdio> #include<algorithm> #include<cstring> using namespace std; #def…

题意:给括号匹配涂色,红色蓝色或不涂,要求见原题,求方案数 区间DP 用栈先处理匹配 f[i][j][0/1/2][0/1/2]表示i到ji涂色和j涂色的方案数 l和r匹配的话,转移到(l+1,r-1) 不匹配,i的匹配p一定在l和r之间,从p分开转移 听说用记忆化搜索比较快,可以像树形DP那样写记忆化搜索,也可以传统的四个参数那样写 用循环+条件判断,简化状态转移的枚举 注意细节 见代码 #include<iostream> #include<cstdio> #include&l…

Brackets Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 3624   Accepted: 1879 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…

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 sequence, then (s) and [s] are regular brackets sequences, and if a and b are regul…

题目链接:Brackets Sequence 题目描写叙述:给出一串由'(')'' [ ' ' ] '组成的串,让你输出加入最少括号之后使得括号匹配的串. 分析:是区间dp的经典模型括号匹配.解说:http://blog.csdn.net/y990041769/article/details/24194605 ,难点在于要把匹配后的括号输出来. 首先我们知道前面定义dp [ i ] [ j ] 为串中第 i 个到第 j 个括号的最大匹配数目 那么假如我们知道随意 i 到 j 从哪儿插入分点使得匹…