题意:一个字符串被定义为“alphabetical”,当且仅当它能够删除一些字符,变成“ab...yz”,给你一个只由小写字母组成的字符串,问你最少插入几个字母,使它变成“alphabetical”的. f(i,j)表示前i个字母,以j为结尾时,最少要插入几个字母. f(i,j)=min{f(i-1,k)+j-k+(s[i]>k && s[i]<=j) ('a'-1<=k<j) , f(i-1,j)}. #include<cstdio> #include…

UVA 1394 And Then There Was One / Gym 101415A And Then There Was One / UVAlive 3882 And Then There Was One / POJ 3517 And Then There Was One / Aizu 1275 And Then There Was One (动态规划,思维题) Description Let's play a stone removing game. Initially, n ston…

题目传送门 传送门 题目大意 给定一个长度为$n$的序列,要求划分成最少的段数,然后将这些段排序使得新序列单调不减. 考虑将相邻的相等的数缩成一个数. 假设没有分成了$n$段,考虑最少能够减少多少划分. 我们将这个序列排序,对于权值相同的一段数可以任意交换它们,每两个相邻数在原序列的位置中如果是$i, i + 1$,那么划分的段数就可以减少1. 每次转移我们考虑添加值相同的一段. 每次转移能不能将减少的段数加一取决于当前考虑的数在前一段内有没有出现以及有没有作为最左端点. 因此我们记录一个决策与…

题目大意是,非你若干个任务,任务分别对应开始时间.预期收益.持续时间三项指标,让你从中选择一个受益最大的方案(没有开始时间相同的任务). 于是,标准状态转移方程应当为,设DP[K]为选择了前K个任务的最大收益,后面转移为DP[K+1]=MAX且能够共存的(DP[I]):很容易想到N^2的暴力更新,但是这题数量太大,会炸得连渣都不剩.于是需要优化到较低的数量级(比如NLOGN) 注意到,我们也许不用对某个任务来选取前K个的最大值,不容易想到优化但是想想刘汝佳同志的话——不方便直接求解的时候想想更新…

Hasan and Bahosain want to buy a new video game, they want to share the expenses. Hasan has a set of N coins and Bahosain has a set of M coins. The video game costs W JDs. Find the number of ways in which they can pay exactly W JDs such that the diff…

A group of contest writers have written n problems and want to use k of them in an upcoming contest. Each problem has a difficulty level. A contest is valid if all of its k problems have different difficulty levels. Compute how many distinct valid co…

求最长上升子序列方案数. 转载自:http://blog.csdn.net/u013445530/article/details/47958617,如造成不便,请博主联系我. 数组A包含N个整数(可能包含相同的值).设S为A的子序列且S中的元素是递增的,则S为A的递增子序列.如果S的长度是所有递增子序列中最长的,则称S为A的最长递增子序列(LIS).A的LIS可能有很多个.例如A为:{1 3 2 0 4},1 3 4,1 2 4均为A的LIS.给出数组A,求A的LIS有多少个.由于数量很大,输出…

给你10个箱子,有长宽高,每个箱子你可以决定哪个面朝上摆.把它们摞在一起,边必须平行,上面的不能突出来,问你最多摆几个箱子. 3^10枚举箱子用哪个面.然后按长为第一关键字,宽为第二关键字,从大到小排序. 如果前面的宽大于等于后面的宽,就连接一条边. 形成一张DAG,拓扑排序后跑最长路即可. #include<cstdio> #include<cstring> #include<queue> #include<algorithm> using namespa…

一般思路的dp是用f(i,j,0)表示前i位最后有j个1的方案数,用f(i,j,1)表示前j位最后有j个2的方案数,j都是大于等于1的,然后比较容易转移. 但这题卡内存,就只能用f(i,j)表示前i位最后有j个1的方案数,这里j大于等于0. 然后转移就略麻烦,自己看代码领会一下吧. 也可以看成是滚动数组优化. #include<cstdio> using namespace std; #define MOD 1000000007 int n,lim[2]; int f[50010][310],…

裸dp,看代码. #include<cstdio> #include<algorithm> #include<cstring> using namespace std; int T,f[12][12][12],n,a[12][12][12]; int main() { freopen("commandos.in","r",stdin); int F,x,y,z; scanf("%d",&T); for(…

azerah.in / azerah.out Por Costel the Pig has received a royal invitation to the palace of the Egg-Emperor of Programming, Azerah. Azerah had heard of the renowned pig and wanted to see him with his own eyes. Por Costel, having arrived at the palace,…

Mrs. Panda’s birthday is coming. Mr. Panda wants to compose a song as gift for her birthday. It is known that Mrs. Panda does not like a song if and only if its lyrics contain Xvowels in a row, or Y consonants in a row (Otherwise, Mrs. Panda likes th…

Hidden Code 题目连接: http://codeforces.com/gym/100015/attachments Description It's time to put your hacking skills to the test! You've been called upon to help crack enemy codes in the current war on... something or another. Anyway, the point is that yo…

C. Palindrome Again !! time limit per test:1 second memory limit per test:64 megabytes input:standard input output:standard output Given string with N characters, your task is to transform it to a palindrome string. It's not as easy as you may think…

BUPT2017 wintertraining(15) #4E Gym - 101138K 题意 N节车厢的火车,每节车厢容量是1~K,那么有\(K^N\)种火车. 求选择D个连续的且容量相同的车厢的方案恰为T种的火车有多少种 模\(10^9+7\). (1 ≤ D ≤ n ≤ 3333, 0 ≤ T ≤ N - D + 1, 1 ≤ K ≤ \(10^9\)). 题解 \(f[i][j]\)表示前i节车厢,恰有j种选择方案的火车数量,那么 初始条件:\(f[0][0]=1\) 状态转移: 我们…

HDU 1074 Doing Homework (动态规划,位运算) Description Ignatius has just come back school from the 30th ACM/ICPC. Now he has a lot of homework to do. Every teacher gives him a deadline of handing in the homework. If Ignatius hands in the homework after the d…

Description Let x and y be two strings over some finite alphabet A. We would like to transform x into y allowing only operations given below: Deletion: a letter in x is missing in y at a corresponding position. Insertion: a letter in y is missing in …

http://codeforces.com/gym/100952/problem/H H. Special Palindrome time limit per test 1 second memory limit per test 64 megabytes input standard input output standard output A sequence of positive and non-zero integers called palindromic if it can be…

http://codeforces.com/gym/100952/problem/C C. Palindrome Again !! time limit per test 1 second memory limit per test 64 megabytes input standard input output standard output Given string with N characters, your task is to transform it to a palindrome…

上一篇我们已经说到了,增强学习的目的就是求解马尔可夫决策过程(MDP)的最优策略,使其在任意初始状态下,都能获得最大的Vπ值.(本文不考虑非马尔可夫环境和不完全可观测马尔可夫决策过程(POMDP)中的增强学习). 那么如何求解最优策略呢?基本的解法有三种: 动态规划法(dynamic programming methods) 蒙特卡罗方法(Monte Carlo methods) 时间差分法(temporal difference). 动态规划法是其中最基本的算法,也是理解后续算法的基础,因此本…

题目:House Robber You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent houses have security system connected a…

March 26, 2013 作者:Hawstein 出处:http://hawstein.com/posts/dp-novice-to-advanced.html 声明:本文采用以下协议进行授权: 自由转载-非商用-非衍生-保持署名|Creative Commons BY-NC-ND 3.0 ,转载请注明作者及出处. 前言 本文翻译自TopCoder上的一篇文章: Dynamic Programming: From novice to advanced ,并非严格逐字逐句翻译,其中加入了自己的…

转自:http://segmentfault.com/blog/exploring/ LCS 问题描述 定义: 一个数列 S,如果分别是两个或多个已知数列的子序列,且是所有符合此条件序列中最长的,则 S 称为已知序列的最长公共子序列. 例如:输入两个字符串 BDCABA 和 ABCBDAB,字符串 BCBA 和 BDAB 都是是它们的最长公共子序列,则输出它们的长度 4,并打印任意一个子序列. (Note: 不要求连续) 判断字符串相似度的方法之一 - LCS 最长公共子序列越长,越相似. Ju…

 //动态规划查找两个字符串最大子串         public static string lcs(string word1, string word2)         {             int max = 0;             int index = 0;             int[,] nums = new int[word1.Length + 1,word2.Length+1];             for (int i = 0; i <= word1.L…

//递归         public static long recurFib(int num)         {             if (num < 2)             {                 return num;             }             else             {                 return recurFib(num - 1) + recurFib(num - 2);             }   …

1. 问题描述 子串应该比较好理解,至于什么是子序列,这里给出一个例子:有两个母串 cnblogs belong 比如序列bo, bg, lg在母串cnblogs与belong中都出现过并且出现顺序与母串保持一致,我们将其称为公共子序列.最长公共子序列(Longest Common Subsequence, LCS),顾名思义,是指在所有的子序列中最长的那一个.子串是要求更严格的一种子序列,要求在母串中连续地出现.在上述例子的中,最长公共子序列为blog(cnblogs, belong),最长公…

[BZOJ1700][Usaco2007 Jan]Problem Solving 解题 Description 过去的日子里,农夫John的牛没有任何题目. 可是现在他们有题目,有很多的题目. 精确地说,他们有P (1 <= P <= 300) 道题目要做. 他们还离开了农场并且象普通人一样找到了工作. 他们的月薪是M (1 <= M <= 1000) 元. 他们的题目是一流的难题,所以他们得找帮手.帮手们不是免费的,但是他们能保证在一个月内作出任何题目.每做一道题需要两比付款,…

 Gym 101047M Removing coins in Kem Kadrãn Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Practice Description standard input/output Andréh and his friend Andréas are board-game aficionados. They know many of their friend…

 Gym 101047K Training with Phuket's larvae Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Practice Description standard input/output Thai cuisine is known for combining seasonings so that every dish has flavors that are…

Gym 101047E Escape from Ayutthaya Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u  Practice  Description standard input/output Ayutthaya was one of the first kingdoms in Thailand, spanning since its foundation in 1350 to…