C - King Arthur's Birthday Celebration POJ - 3682 King Arthur is an narcissist who intends to spare no coins to celebrate his coming K-th birthday. The luxurious celebration will start on his birthday and King Arthur decides to let fate tell when to…

King Arthur is an narcissist who intends to spare no coins to celebrate his coming K-th birthday. The luxurious celebration will start on his birthday and King Arthur decides to let fate tell when to stop it. Every day he will toss a coin which has p…

传送门 题意 进行翻硬币实验,若k次向上则结束,进行第n次实验需花费2*n-1的费用,询问期望结束次数及期望结束费用 分析 我们令f[i]为结束概率 \[f[i]=C_{i-1}^{k-1}*p^k*(1-p)^{i-k}\] \[\sum f[i]=1(关键)\] \(ans1=\sum f[i]\) \(=\sum i*C_{i-1}^{k-1}*p^k*(1-p)^{i-k}\) \(=p^k*k*\sum C_i^k*(1-p)^{i-k}\) \(=k/p\) \(ans2=\sum…

也许更好的阅读体验 \(\mathcal{Description}\) 每天抛一个硬币,硬币正面朝上的几率是p,直到抛出k次正面为止结束,第\(i\)天抛硬币的花费为\(2i-1\),求出抛硬币的天数的期望和花费的期望. \(\mathcal{Solution}\) 该题为双倍经验题,具体做法请看 收集邮票 (原谅我的懒惰,但这可以认为是一样的题了) 这里我们求\(f\)数组的过程将概率改为\(p\),求\(g\)时,将里面的\(f[i]\)与\(f[i+1]\)全部乘以2即可 注意 本题输出有…

题意:进行翻硬币实验,若k次向上则结束,进行第n次实验需花费2*n-1的费用,询问期望结束次数及期望结束费用 设F[i]为第i次结束时的概率 F[i]=  c(i-1,k-1)*p^k*(1-p)^(i-k) sigma(f[i])==1 p^k*sigma(c(i-1,k-1)*(1-p)^(i-k))=1 sigma(c(i-1,k-1)*(1-p)^(i-k))=1/(p^k) ans1=sigma(i*f[i]) =p^k*sigma(i*c(i-1,k-1)*(1-p)^(i-k))…

每天抛一个硬币,硬币正面朝上的几率是p,直到抛出k次正面为止结束,第一天抛硬币需花费1,第二天花费3,然后是5,7,9……以此类推,让我们求出抛硬币的天数的期望和花费的期望. 天数期望: A.投出了k-1个硬币正面朝上花费了E(k-1)天,再投出一个硬币正面朝上(概率为p,花费时间+1天):B.投出了k个硬币正面朝上花费了E(k)天,投出一个硬币反面朝上(概率为1-p,花费时间+1天).分析的时候不能漏掉B情况,得到关系式:E(k)=p*(E(k-1)+1)+(1-p)*(E(k)+1),整理可…

传送门 解题思路 第一问比较简单,设$f[i]​$表示扔了$i​$次正面向上的硬币的期望,那么有转移方程 : $f[i]=f[i]*(1-p)+f[i-1]*p+1​$,意思就是$i​$次正面向上可以由$i-1​$次扔一个正面或者$i​$次扔一个背面得到,化简后可得 : $f[i]=f[i-1]+1/p​$. 第二问就比较玄学了,设$g[i]$表示扔了$i$次正面向上花费的期望,那么考虑如果第$i$次到正面,其实次数等于$f[i-1]+1$,如果扔到背面,次数等于$f[i]+1$.所以转移方程:…

King Arthur is an narcissist who intends to spare no coins to celebrate his coming K-th birthday. The luxurious celebration will start on his birthday and King Arthur decides to let fate tell when to stop it. Every day he will toss a coin which has p…

King Arthur's Knights Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1415 Accepted Submission(s): 612 Special Judge Problem Description I am the bone of my sword. Steel is my body, and the fire i…

King Arthur's KnightsTime Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2752    Accepted Submission(s): 1086Special Judge Problem DescriptionI am the bone of my sword. Steel is my body, and the fir…

Problem poj-3682 题目大意:抛一次硬币有\(p\)的概率得到正面,当有\(n\)次正面时停止,抛第\(i\)次的花费为\(2i-1\),求抛的期望次数和期望花费 Solution 本来做这题就是想巩固一下期望方面的东西,可能有点拓展 第一问比较明显,设\(f_i\)表示抛掷了\(i\)次时的期望天数,依题意有: \(f_i=p\cdot f_{i-1}+(1-p)\cdot f_i+1\) 解释一下,对于抛一次,有\(p\)的概率正面,只要再抛\(f_{i-1}\)次即可,所以加…

n积分m文章无向边 它输出一个哈密顿电路 #include <cstdio> #include <cstring> #include <iostream> using namespace std; const int N = 155; int n, m; bool mp[N][N]; int S, T, top, Stack[N]; bool vis[N]; void _reverse(int l,int r) { while (l<r) swap(Stack[l…

King Arthur's Birthday Celebration Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 3575   Accepted: 1130 Description King Arthur is an narcissist who intends to spare no coins to celebrate his coming K-th birthday. The luxurious celebrat…

Knights of the Round Table Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 12439   Accepted: 4126 Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the oth…

Knights of the Round Table Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 10911   Accepted: 3587 Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the oth…

Knights of the Round Table Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the other knights are fun things to do. Therefore, it is not very surprising that in recent…

Knights of the Round Table Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 9169   Accepted: 2960 Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the othe…

Knights of the Round Table Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 10804   Accepted: 3553 Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the oth…

Magician Time Limit: 18000/9000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 1771    Accepted Submission(s): 515 Problem Description Fantasy magicians usually gain their ability through one of three usual methods…

Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 3119   Accepted: 1455 Description Centuries ago, King Arthur and the Knights of the Round Table used to meet every year on New Year's Day to celebrate their fellowship. In remembrance of th…

1.获取文本语料库 NLTK库中包含了大量的语料库,下面一一介绍几个: (1)古腾堡语料库:NLTK包含古腾堡项目电子文本档案的一小部分文本.该项目目前大约有36000本免费的电子图书. >>>import nltk >>>nltk.corpus.gutenberg.fileids() ['austen-emma.txt','austen-persuasion.txt' 'austen-sense.txt', 'bible-kjv.txt', 'blake-poems.…

转自:http://blog.csdn.net/shahdza/article/details/7779385 欧拉回路[HDU]1878 欧拉回路 判断3018 Ant Trip 一笔画问题1116 Play on Words2894 DeBruijin 兹鼓欧拉回路1956 Sightseeing tour 混合欧拉3472 HS BDC 混合欧拉=========================================================================…

Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, anddrinking with the other knights are fun things to do. Therefore, it is not very surprising that in recentyears the kingdom of King Arthur has exp…

BFS.先算出棋盘上每个点到各个点knight需要的步数:然后枚举所有点,其中再枚举king是自己到的还是knight带它去的(假如是knight带它的,枚举king周围的2格(网上都这么说,似乎是个结论?还是usaco数据太弱了?不过看跑出来的时间,全部枚举或许也可以)).一开始觉得挺麻烦的,不过只要思路清晰写起来应该也没多大问题.大概就是这样了. -------------------------------------------------------------------------…

Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the other knights are fun things to do. Therefore, it is not very surprising that in recent years the kingdom of King…

CamelotIOI 98 Centuries ago, King Arthur and the Knights of the Round Table used to meet every year on New Year's Day to celebrate their fellowship. In remembrance of these events, we consider a board game for one player, on which one chesspiece king…

初学PHP的时候使用了一些文件读取API,但是没有真正弄清楚各API的区别以及差异,于是找了一篇学习了一下,贴在这里,引用自IBM社区的一篇文章, 整体整理测试如下 <?php /** * Created by PhpStorm. * User: f3ngt1ng * Date: 2017/2/15 * Time: 9:11 */ //The right way to read files with php //URL:https://www.ibm.com/developerworks/lib…

Fantasy magicians usually gain their ability through one of three usual methods: possessing it as an innate talent, gaining it through study and practice, or receiving it from another being, often a god, spirit, or demon of some sort. Some wizards ar…

Time Limit: 7000MS   Memory Limit: 65536K Total Submissions: 13954   Accepted: 4673 Description Being a knight is a very attractive career: searching for the Holy Grail, saving damsels in distress, and drinking with the other knights are fun things t…

Graphviz Windows环境安装: 1.官网下载 官网下载地址 2.配置环境变量 将graphviz安装目录下的bin文件夹添加到Path环境变量中: 3.验证是否安装并配置成功 进入windows命令行界面,输入dot -version,然后按回车,如果显示graphviz的相关版本信息,则安装配置成功.如图: 4.python环境中安装:(pycharm中) 然后输入Graphivz安装 5.在pycharm中运行 # coding:utf-8 from graphviz impor…