题面传送门 题意: 给出 \(s_0,s_1,s_2,\dots,s_{n-1}\),对于 \(i\geq n\),有 \(m\) 个 \(s_i\) 满足 \(s_i\neq s_{i\bmod n}\),这 \(m\) 个 \(s_i\) 特殊给定,其它的 \(s_i=s_{i\bmod n}\). 另有序列 \(f_i\) 满足 \(f_0=0,f_1=1\),\(f_i=f_{i-1}s_{i-1}+f_{i-2}s_{i-2}\). 求 \(f_x\bmod P\). \(1\leq…

题意: 定义类循环序列为 长度无限,且除了有限个元素外,均满足s[i] ≡ s[i mod N] (i≥N). 现在有数列F,定义为 F[i] = s[i-2]*F[i-1] + s[i-1]*F[i-1],特别的,F[0] = 0, F[1] = 1. 给定正整数K,P,N代表要求输出的答案为F[k] mod P,类循环序列s的长度为N. 接下来给出s[0]..s[n-1]. 然后是一个正整数M,代表不满足循环条件的元素个数. 接下来M行每行两个正整数j,v表示s[j] = v,保证所有j不同…

Fibonotci sequence is an integer recursive sequence defined by the recurrence relation Fn = sn - 1·Fn - 1 + sn - 2·Fn - 2withF0 = 0, F1 = 1 Sequence s is an infinite and almost cyclic sequence with a cycle of length N. A sequence s is called almost c…

上一次我们拿学校的URP做了个小小的demo.... 其实我们还可以把每个学生的证件照爬下来做成一个证件照校花校草评比 另外也可以写一个物理实验自动选课... 但是出于多种原因,,还是绕开这些敏感话题.. 今天,我们来扒一下cf的题面! PS:本代码不是我原创 1. 必要的分析 1.1 页面的获取 一般情况CF的每一个 contest 是这样的: 对应的URL是:http://codeforces.com/contest/xxx 还有一个Complete problemset页面,它是这样的:…

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…

http://codeforces.com/contest/738/problem/C Vasya is currently at a car rental service, and he wants to reach cinema. The film he has bought a ticket for starts in t minutes. There is a straight road of length s from the service to the cinema. Let's…

http://codeforces.com/contest/738/problem/A Polycarp has interviewed Oleg and has written the interview down without punctuation marks and spaces to save time. Thus, the interview is now a string s consisting of n lowercase English letters. There is…

http://codeforces.com/problemset/problem/662/A 题目大意: 给定n(n <= 500000)张卡片,每张卡片的两个面都写有数字,每个面都有0.5的概率是在正面,各个卡牌独立.求把所有卡牌来玩Nim游戏,先手必胜的概率. (⊙o⊙)-由于本人只会在word文档里写公式,所以本博客是图片格式的. Code #include <cstdio> #include <cstring> #include <algorithm> u…

http://codeforces.com/problemset/problem/274/B 题目大意: 给定你一颗树,每个点上有权值. 现在你每次取出这颗树的一颗子树(即点集和边集均是原图的子集的连通图)且这颗树中必须包含节点1 然后将这颗子树中的所有点的点权+1或-1 求把所有点权全部变为0的最小次数(n<=10^5) 题解: 因为每一次的子树中都必须有1,所以我们得知每一次变换的话1的权值都会变化 所以我们以1为根 现在,我们发现,如果一个节点的权值发生变化,那么他的父节点的权值一定发生变…

http://codeforces.com/problemset/problem/261/B 题目大意:给定n个数a1-an(n<=50,ai<=50),随机打乱后,记Si=a1+a2+a3-+ai,问满足Si<=p的i的最大值的期望.(p<=50) (大意来自于http://www.cnblogs.com/liu-runda/p/6253569.html) 我们知道,全排列其实等价于我们一个一个地等概率地向一个序列里面插入数值 所以我们可以这么看这道题: 现在有n个数,有n个盒子…