给一些字符 求它们能拼成的字符串 的回文子串的个数最大值 对应的那个字符串 就是把相同的都放一起是最优的,排下序就行了... #include<bits/stdc++.h> #define pa pair<int,int> #define CLR(a,x) memset(a,x,sizeof(a)) using namespace std; typedef long long ll; ; inline ll rd(){ ll x=;; ;c=getchar();} +c-',c=g…

嘟嘟嘟 只要将每一种字母放一块输出就行了. 证明1:比如 1 2 3 4 5 6,那么这个序列对答案的贡献分别是1和5,2和4 ,3和6……如果重新排列成x x x x o o,会发现对          x x o x x o 答案的贡献不变,所以得证. 证明2:字母ai有xi个,那么对答案的最大贡献为xi * (xi - 1) / 2,重排后能达到理论上界,所以为最优解. #include<cstdio> #include<iostream> #include<cmath…

考虑在一个部分串中加入字符使得最终构造的串回文子串最多的方案 考虑简单情况,对于只含一种元素的串,我们要插入其他元素 记原有元素为$a$,新加元素为$b$ 考虑$b$的最优插入位置 原串$aaaa...aa$,插入$b$ 设$b$在串中的插入位置为$pos$,插入后,原本的回文串$[pos-i,pos+j](i!=j)$会因此不匹配 所以这样不会使得原串匹配结果变多 所以我们要让各个元素独立才是最优方案 #include<iostream> #include<cstdio> usi…

C. No to Palindromes! time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Paul hates palindromes. He assumes that string s is tolerable if each its character is one of the first p letters of th…

1692: [Usaco2007 Dec]队列变换 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 1383  Solved: 582[Submit][Status][Discuss] Description FJ打算带他的N(1 <= N <= 30,000)头奶牛去参加一年一度的“全美农场主大奖赛”.在这场比赛中,每个参赛者都必须让他的奶牛排成一列,然后领她们从裁判席前依次走过. 今年,竞赛委员会在接受队伍报名时,采用了一种新的登记规则:他们把所…

Wooden Sticks Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 15564    Accepted Submission(s): 6405 Problem Description There is a pile of n wooden sticks. The length and weight of each stick a…

FatMouse' Trade Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 56784    Accepted Submission(s): 19009 Problem Description FatMouse prepared M pounds of cat food, ready to trade with the cats g…

1691: [Usaco2007 Dec]挑剔的美食家 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 786  Solved: 391[Submit][Status][Discuss] Description 与很多奶牛一样,Farmer John那群养尊处优的奶牛们对食物越来越挑剔,随便拿堆草就能打发她们午饭的日子自然是一去不返了.现在,Farmer John不得不去牧草专供商那里购买大量美味多汁的牧草,来满足他那N(1 <= N <= 100,…

http://codeforces.com/contest/738/problem/D Galya is playing one-dimensional Sea Battle on a 1 × n grid. In this game a ships are placed on the grid. Each of the ships consists of bconsecutive cells. No cell can be part of two ships, however, the shi…

4245: [ONTAK2015]OR-XOR Time Limit: 10 Sec  Memory Limit: 256 MBSubmit: 486  Solved: 266[Submit][Status][Discuss] Description 给定一个长度为n的序列a[1],a[2],...,a[n],请将它划分为m段连续的区间,设第i段的费用c[i]为该段内所有数字的异或和,则总费用为c[1] or c[2] or ... or c[m].请求出总费用的最小值. Input 第一行包含…