4758: [Usaco2017 Jan]Subsequence Reversal Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 76  Solved: 52[Submit][Status][Discuss] Description Farmer John is arranging his NN cows in a line to take a photo (1≤N≤50). The height of the iith co w in sequ…

Palindrome subsequence Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 131072/65535 K (Java/Others) Total Submission(s): 2836 Accepted Submission(s): 1160 Problem Description In mathematics, a subsequence is a sequence that can be derived from a…

4760: [Usaco2017 Jan]Hoof, Paper, Scissors Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 136  Solved: 100[Submit][Status][Discuss] Description You have probably heard of the game "Rock, Paper, Scissors". The cows like to play a similar game th…

In mathematics, a subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements. For example, the sequence <A, B, D> is a subsequence of <A, B, C, D, E, F>. (…

Palindrome subsequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/65535 K (Java/Others)Total Submission(s): 558    Accepted Submission(s): 203 Problem Description In mathematics, a subsequence is a sequence that can be derived fro…

Palindrome subsequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/65535 K (Java/Others) Total Submission(s): 2595    Accepted Submission(s): 1039 Problem Description In mathematics, a subsequence is a sequence that can be derived…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4632 题意:给你一个序列,问你该序列中有多少个回文串子序列,可以不连续. 思路:dp[i][j]表示序列i到j中具有的回文串序列数. 当s[i]==s[j], dp[i][j]=dp[i+1][j]+dp[i][j-1]+1 否则 dp[i][j]=dp[i+1][j]+dp[i][j-1]-dp[i+1][j-1]: #include <iostream> #include <cstdio…

区间\(dp\)提升复习 不得不说这波题真的不简单... 技巧总结: 1.有时候转移可以利用背包累和 2.如果遇到类似区间添加限制的题可以直接把限制扔在区间上,每次只考虑\([l,r]\)被\([i,j]\)完全包含的情况 [BZOJ4897] [Thu Summer Camp2016] 成绩单 典型的利用背包转移,\(dp[i][j]\)表示处理完这段\([i,j]\)区间的答案 转移时一段区间可以被先处理掉或者直接从已经处理完的\(dp[i][j]\)中取过来,这个可以用一个背包维护 con…

Problem Description In mathematics, a subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements. For example, the sequence <A, B, D> is a subsequence of <A,…

1719: [Usaco2006 Jan] Roping the Field 麦田巨画 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 82  Solved: 26[Submit][Status][Discuss] Description Farmer John is quite the nature artist: he often constructs large works of art on his farm. Today, FJ wants…

Palindrome subsequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/65535 K (Java/Others)Total Submission(s): 4513    Accepted Submission(s): 1935 Problem Description In mathematics, a subsequence is a sequence that can be derived f…

题目 参考自博客:http://blog.csdn.net/u011498819/article/details/38356675 题意:查找这样的子回文字符串(未必连续,但是有从左向右的顺序)个数. 简单的区间dp,哎,以为很神奇的东西,其实也是dp,只是参数改为区间,没做过此类型的题,想不到用dp,以后就 知道了,若已经知道[0,i],推[0,i+1], 显然还要从i+1 处往回找,dp方程也简单: dp[j][i]=(dp[j+1][i]+dp[j][i-1]+10007-dp[j+1][…

题意 给定一个字符串,问有多少个回文子串(两个子串可以一样). 思路 注意到任意一个回文子序列收尾两个字符一定是相同的,于是可以区间dp,用dp[i][j]表示原字符串中[i,j]位置中出现的回文子序列的个数,有递推关系: dp[i][j]=dp[i+1][j]+dp[i][j-1]-dp[i+1][j-1]  (*) 如果i和j位置出现的字符相同,那么dp[i][j]可以由dp[i+1][j-1]中的子序列加上这两个字符构成回文子序列,也就是 dp[i][j]+=dp[i+1][j-1],注意…

题意1:问你一个串有几个不连续子序列(相同字母不同位置视为两个) 题意2:问你一个串有几种不连续子序列(相同字母不同位置视为一个,空串视为一个子序列) 思路1:由容斥可知当两个边界字母相同时 dp[i][j] = dp[i + 1][j] + dp[i][j - 1] - dp[i + 1][j - 1] + dp[i + 1][j - 1] + 1;当两个字母不同时 dp[i][j] = dp[i + 1][j] + dp[i][j - 1] - dp[i + 1][j - 1].然后区间DP…

题目链接 题目大意 给你几个字符串 (1<len(s)<1000) ,要你求每个字符串的回文序列个数.对于10008取模. Solution 区间DP. 比较典型的例题. 状态定义: 令 \(f[i][j]\) 表示 \(i\) 到 \(j\) 的回文序列个数,\(s\) 为给出的字符串. 状态转移: \(s[i]\neq s[j]\) 那么此时 \(f[i][j]\) 即为\(f[i][j-1]\),\(f[i+1][j]\)之和. 但由于 \(i+1->j-1\)的我们明显重复统计了…

题目链接 http://poj.org/problem?id=1141 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 reg…

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…

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…

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…

也写了好几天的区间DP了,这里稍微总结一下(感觉还是不怎么会啊!). 但是多多少少也有了点感悟: 一.在有了一点思路之后,一定要先确定好dp数组的含义,不要模糊不清地就去写状态转移方程. 二.还么想好...想到了再加上去.... 之前也看了别人的总结,也给出了不少区间DP的模板.这里我也贴一下基本的模板: 区间DP模板 ; len < n; len++) { //操作区间的长度 ; i+len <= n; i++) { //始末 int j=i+len; //检查是否匹配(非必须) for (…

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…

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…

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…

Palindrome subsequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/65535 K (Java/Others)Total Submission(s): 2858    Accepted Submission(s): 1168 Problem Description In mathematics, a subsequence is a sequence that can be derived f…

个人心得:今天就做了这些区间DP,这一题开始想用最长子序列那些套路的,后面发现不满足无后效性的问题,即(,)的配对 对结果有一定的影响,后面想着就用上一题的思想就慢慢的从小一步一步递增,后面想着越来越大时很多重复,应该要进行分割, 后面想想又不对,就去看题解了,没想到就是分割,还是动手能力太差,还有思维不够. ;j+i<ch.size();j++) { if(check(j,j+i)) dp[j][j+i]=dp[j+][j+i-]+; for(int m=j;m<=j+i;m++) dp[j…

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…

题目链接:https://vjudge.net/problem/POJ-2955 Brackets Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 9630   Accepted: 5131 Description We give the following inductive definition of a “regular brackets” sequence: the empty sequence is a regu…

Brackets Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 8017   Accepted: 4257 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…

题解报告:poj 2955 Brackets(括号匹配) 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 sequen…