题目描述:https://www.luogu.org/problemnew/show/CF838D(有翻译) (为什么博客园把我刚写的给吞了……orz) 这题当初看的十分懵逼,不过听了肖大佬的做法还是很清楚的. 因为乘客们可以从双向进入,然后乘客只会看给自己安排的座位和后面的空座位,所以我们不如直接新建一个虚拟座位,把这个序列变成一个环.乘客在找不到真实座位中找不到座位了,自然就会坐到虚拟位置上.因此,如果一个方案中虚拟位置被坐了说明不合法,否则就合法. 虚拟位置与其他位置一样是一个普通的座位,…

传送门:https://www.luogu.org/problemnew/show/CF838D 这道题反正我自己想是毫无头绪,最后还是听了肖大佬的做法. 因为题中说乘客可以从前后门进来,所以我们可以把这n个作为想象成一个环,然后乘客们都从n + 1的位置出发,于是从前后门就变成了顺逆时针. 很容易得出,所有方案为 [2 * (n +1)] ^ m 种,但是这其中包含了不合法方案,所以要减去不合法的情况.那么什么是不合法的情况呢?一个人转了一圈又回到了 n + 1 号的座位,就说明他没有找到位置…

洛谷题面传送门 题解里一堆密密麻麻的 Raney 引理--蒟蒻表示看不懂,因此决定写一篇题解提供一个像我这样的蒟蒻能理解的思路,或者说,理解方式. 首先我们考虑什么样的牌堆顺序符合条件.显然,在摸牌任意时刻,你手中的牌允许你继续无限制摸的牌是一段区间,即存在一个位置 \(p\),满足你在不使用新摸出来的牌的机会下能够恰好摸到第 \(p\) 张牌.考虑如果我们新摸出来一张牌会产生怎样的影响,假设摸出一张 \(w_i=x\) 的牌,那么我们肯定会在耗完目前手中牌的机会,也就是摸完第 \(p\)​ 张…

Suppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true for the ith position (1 ≤ i ≤ N) in this array: The number at the ith position…

The 11th Zhejiang Provincial Collegiate Programming Contest is coming! As a problem setter, Edward is going to arrange the order of the problems. As we know, the arrangement will have a great effect on the result of the contest. For example, it will…

B - Problem Arrangement Time Limit:2000MS     Memory Limit:65536KB     64bit IO Format:%lld & %llu Submit Status Practice ZOJ 3777 Description The 11th Zhejiang Provincial Collegiate Programming Contest is coming! As a problem setter, Edward is going…

Given two integers n and k, you need to construct a list which contains n different positive integers ranging from 1 to n and obeys the following requirement: Suppose this list is [a1, a2, a3, ... , an], then the list [|a1 - a2|, |a2 - a3|, |a3 - a4|…

Suppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true for the ith position (1 ≤ i ≤ N) in this array: The number at the ith position…

Suppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true for the ith position (1 <= i <= N) in this array: The number at the ith positi…

Info:DescriptionHave you ever wanted to build your own Airplane Physics using the Rigidbody component in Unity 3D? Do you want to know more about setting up modular code to make your workflows faster and more re-usable? If so, this course is for you!…

题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3777 Time Limit: 2 Seconds      Memory Limit: 65536 KB The 11th Zhejiang Provincial Collegiate Programming Contest is coming! As a problem setter, Edward is going to arrange the order…

Fast Arrangement Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 3995    Accepted Submission(s): 1141 Problem Description Chinese always have the railway tickets problem because of its' huge amo…

题目链接:New Year and Arbitrary Arrangement 题意: 有一个ab字符串,初始为空. 用Pa/(Pa+Pb)的概率在末尾添加字母a,有 Pb/(Pa+Pb)的概率在末尾添加字母b,当出现≥k个ab子串时立即停止添加字母,求最后期望的ab子串个数.(子串ab不要求连续) 例子:当k=1,aab含2个ab,bbabbab时不可能出现的,因为到了bbab就会停止添加字母. 题解: 期望DP DP果然是智商的分界线 orz @.@#,这题题意其实我也没看太懂,后来看了别人…

Fast Arrangement Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 3563    Accepted Submission(s): 1024 Problem Description Chinese always have the railway tickets problem because of its' huge amo…

[题目]Good Bye 2017 D. New Year and Arbitrary Arrangement [题意]给定正整数k,pa,pb,初始有空字符串,每次有pa/(pa+pb)的可能在字符串末尾+a,有pb/(pa+pb)的可能在字符串末尾+b,求加到组成至少k对子序列“ab"时的期望子序列“ab”数.k<=1000,pa,pb<=10^6. [算法]期望DP [题解]主要问题在于字符串无限延伸,那么需要考虑记录前缀的关键量来为DP设置终止状态. 设f[i][j]表示前缀…

Suppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true for the ith position (1 <= i <= N) in this array: The number at the ith positi…

Problem A. Arrangement of Contest 题目连接: http://codeforces.com/gym/100269/attachments Description Little Dmitry and little Petr want to arrange a contest. Their little friends submitted several task proposals and now Dmitry and Petr want to select som…

原题链接在这里:https://leetcode.com/problems/beautiful-arrangement-ii/description/ 题目: Given two integers n and k, you need to construct a list which contains n different positive integers ranging from 1 to n and obeys the following requirement: Suppose thi…

原题链接在这里:https://leetcode.com/problems/beautiful-arrangement/description/ 题目: Suppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true fo…

题目:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3721 来源:http://acm.hust.edu.cn/vjudge/contest/view.action?cid=26644#problem/F Final Exam Arrangement Time Limit: 4 Seconds      Memory Limit: 65536 KB      Special Judge In Zhejiang Univ…

Description The 11th Zhejiang Provincial Collegiate Programming Contest is coming! As a problem setter, Edward is going to arrange the order of the problems. As we know, the arrangement will have a great effect on the result of the contest. For examp…

Description The 11th Zhejiang Provincial Collegiate Programming Contest is coming! As a problem setter, Edward is going to arrange the order of the problems. As we know, the arrangement will have a great effect on the result of the contest. For examp…

Seating Arrangement Mr. Teacher老师班上一共有n个同学,编号为1到n. 在上课的时候Mr. Teacher要求同学们从左至右按1, 2, -, n的顺序坐成一排,这样每个同学的位置是固定的,谁没来上课就一目了然了. 但是时间长了之后,Mr. Teacher发现坐得离得远的同学往往因为交流很少而逐渐变得生疏了,于是他决定重新安排同学们的座位,并且在新的座位安排中,任意两个相邻的同学的编号之差的绝对值都必须大于d. 现在Mr. Teacher需要你帮忙给出一个座位安排方…

1997: Seating Arrangement Description Mr. Teacher老师班上一共有n个同学,编号为1到n. 在上课的时候Mr. Teacher要求同学们从左至右按1, 2, …, n的顺序坐成一排,这样每个同学的位置是固定的,谁没来上课就一目了然了. 但是时间长了之后,Mr. Teacher发现坐得离得远的同学往往因为交流很少而逐渐变得生疏了,于是他决定重新安排同学们的座位,并且在新的座位安排中,任意两个相邻的同学的编号之差的绝对值都必须大于d. 现在Mr. Tea…

1997: Seating Arrangement Time Limit: 1 Sec     Memory Limit: 128 Mb     Submitted: 543     Solved: 171 Description Mr. Teacher老师班上一共有n个同学,编号为1到n. 在上课的时候Mr. Teacher要求同学们从左至右按1, 2, …, n的顺序坐成一排,这样每个同学的位置是固定的,谁没来上课就一目了然了. 但是时间长了之后,Mr. Teacher发现坐得离得远的同学往…

设状态f[i][j]表示有i个a,j个ab的期望 发现如果i+j>=k的话就再来一个b就行了. #include <iostream> #include <cstdio> #include <cstring> using namespace std; +; ][]; int ksm(int d,int z) { ; while(z) { ) res=(1ll*res*d)%mod; d=(1ll*d*d)%mod; z>>=; } return res…

/* HDU4572 Bottles Arrangement http://acm.hdu.edu.cn/showproblem.php?pid=4572 数论 找规律 题意:有m行n列和1-n的数各n个,将其填在m×n的格子里 要求同一列中的数各不相同,同一行中相邻两数的差的绝对值不超过1. 求每一行中值的和的最小值. 这道题很神奇,比赛的时候yy了一发交了上去,没想到真的A了 赛后看题解,发现大家各种yy,然而没有人和我的yy一样, 也许我脑洞过于新奇吧23333 首先这个值肯定比n*m要小…

Sereja and the Arrangement of Numbers 题解: ummm. 在一副图中,如果全部点的度数是偶数/只有2个点是奇数,则能一笔画. 考虑图的点数k为奇数的时候,那么每个点的度数都是偶数点,所以就是可以一笔画,答案为 1 +k * (i - kll) / 2; k为偶数的时候,所有的点是奇数点,我们保留2个点是奇数点,将其他的点改为偶数点,就可以一笔画了.  1 +k * (i - kll) / 2 + k/2 - 1. 代码: #include<bits/stdc…

Problem Arrangement ZOJ - 3777 题目大意:有n道题,第i道题第j个做可以获得Pij的兴趣值,问至少得到m兴趣值的数学期望是多少,如果没有的话就输出No solution. 数学期望很好求,求出符合的方案数与总方案之比就是概率,概率的倒数就是期望.问题在于怎么安排这些题目的做题顺序,如果直接暴力的话,有12!种情况,铁定超时,所以我们可以转换成dp的思想,总共就是12道题,也就212-1种状态,我们枚举每个状态得多少分时的方案数,最终符合的方案数就是dp[212-1]…

uppose you have N integers from 1 to N. We define a beautiful arrangement as an array that is constructed by these N numbers successfully if one of the following is true for the ith position (1 <= i <= N) in this array: The number at the ith positio…