题目链接 题意 : 实际上可以转化一下题意 要求求出用三个不同元素的字符集例如 { 'A' .'B' .'C' } 构造出长度为 n 且不包含 AAA.BBB CCC.ACB BCA.CAC CBC 这其中任意一个字符串的方案数 分析 : 方法一 (BM 求线性递推) 直接暴力出前 10 项的答案.然后猜它其实可以由线性递推递推而来 丢进杜教的 BM 模板里面就可以直接求出第 N 项了 实际上这个可以不用猜.这种不包含某些串的题目 如果你做过类似的.就会知道实际上是可以构造出一个矩阵然后快速幂…

God Water likes to eat meat, fish and chocolate very much, but unfortunately, the doctor tells him that some sequence of eating will make them poisonous. Every hour, God Water will eat one kind of food among meat, fish and chocolate. If there are 3 c…

https://nanti.jisuanke.com/t/31721 题意 有肉,鱼,巧克力三种食物,有几种禁忌,对于连续的三个食物:1.这三个食物不能都相同:2.若三种食物都有的情况,巧克力不能在中间:3.如果两边是巧克力,中间不能是肉或鱼.求方案数. 分析 将meat ,  chocolate,fish 用 0 ,1 , 2 表示. 对于 n 来说,我们只关注后两位,因为 若 n - 1 的所有方案解决的话,我们在 n - 1 的方案添加0, 1,2 就行,然后根据禁忌 去除不可能的方案.…

Just Pour the Water Time Limit: 2 Seconds      Memory Limit: 65536 KB Shirly is a very clever girl. Now she has two containers (A and B), each with some water. Every minute, she pours half of the water in A into B, and simultaneous pours half of the…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=6155 题意: 题解来自:http://www.cnblogs.com/iRedBean/p/7398272.html 先考虑dp求01串的不同子序列的个数. dp[i][j]表示用前i个字符组成的以j为结尾的01串个数. 如果第i个字符为0,则dp[i][0] = dp[i-1][1] + dp[i-1][0] + 1,dp[i][1] = dp[i-1][1] 如果第i个字符为1,则dp[i][1…

God Water likes to eat meat, fish and chocolate very much, but unfortunately, the doctor tells him that some sequence of eating will make them poisonous. Every hour, God Water will eat one kind of food among meat, fish and chocolate. If there are 3 c…

God Water likes to eat meat, fish and chocolate very much, but unfortunately, the doctor tells him that some sequence of eating will make them poisonous. Every hour, God Water will eat one kind of food among meat, fish and chocolate. If there are 33 …

本题算是签到题,但由于赛中花费了过多的时间去滴吧格,造成了不必要的浪费以及智商掉线,所以有必要记录一下坑点 题意:方格从1到n,每一格mjl可以选择吃鱼/巧克力/鸡腿,求走到n格时满足 1.每三格不可重复同一种食物 2.每三格均不同食物时中间格子不可吃巧克力 3.每三格前后两格不可同时吃巧克力 以上三个条件的方案数,n<1e10 太长不看版:打表+快速幂AC 长篇吐槽版 很显然的,设\(dp[n][i][j][k]\),走到第\(n\)格时第\(n-2\)格的食物是\(i\),第\(n-1\)的…

题目顺序:A F G H I K L 做题链接 A. Magic Mirror 题意:判断 给出的 字符串 是否等于"jessie",需要判断大小写 题解:1.用stl库 tolower ... 2.用ascii码将大写转换为小写,例如: 'A' + 32 = 'a' *F. Modular Production Line 题解:网络流最长区间K覆盖问题, 洛谷P3358 参考题解 参考代码 G. Give Candies 题意:n个小朋友,n个糖,每个小朋友按顺序拿随机数量个糖,直到…

2019-ACM-ICPC-沈阳区网络赛-K. Guanguan's Happy water-高斯消元+矩阵快速幂 [Problem Description] 已知前\(2k\)个\(f(i)\),且\(f(n)=f(n-1)\cdot p(1)+f(n-2)\cdot p(2)+\dots+f(n-k)\cdot p(k)\).求\(f(1)+f(2)+\dots+f(n)\). [Solution] 根据题目条件可知 \[ f(k+1)=f(k)\cdot p(1)+f(k-2)\cdot…