题意: 就是由2k 个数 每次选一个 可以选同样的 围成一个圈 使得相邻的数同或为真  求方案数 解析: 第一个数有2k 种选择 之后的n-2个数 都有2k-1 种选择 第n个数 我们要考虑 它的左右两个数 是否一样 一样的话 就是2k - 1 种选择, 不一样的话就是2k - 2 种选择 如果一样是不是就可以看作一共有n-1个数 求方案数..所以递归一下就好了 但左右两个数一样的情况 不还得乘上最后一种的2k-1吗  请看以下...解释.. #include <bits/stdc++.h>…

ACM-ICPC 2018 徐州赛区网络预赛 A.Hard to prepare 枚举第一个选的,接下来的那个不能取前一个的取反 \(DP[i][0]\)表示选和第一个相同的 \(DP[i][1]\)表示选和第一个取反的 \(DP[i][2]\)表示选其他的 状态转移方程直接看代码好了 //#pragma GCC optimize("O3") //#pragma comment(linker, "/STACK:1024000000,1024000000") #inc…

H.Ryuji doesn't want to study 27.34% 1000ms 262144K   Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That…

传送门 题面: In a world where ordinary people cannot reach, a boy named "Koutarou" and a girl named "Sena" are playing a video game. The game system of this video game is quite unique: in the process of playing this game, you need to consta…

In a world where ordinary people cannot reach, a boy named "Koutarou" and a girl named "Sena" are playing a video game. The game system of this video game is quite unique: in the process of playing this game, you need to constantly fac…

262144K   Ryuji is not a good student, and he doesn't want to study. But there are n books he should learn, each book has its knowledge a[i]a[i]. Unfortunately, the longer he learns, the fewer he gets. That means, if he reads books from ll to rr, he…

262144K   Morgana is learning computer vision, and he likes cats, too. One day he wants to find the cat movement from a cat video. To do this, he extracts cat features in each frame. A cat feature is a two-dimension vector <x, y>. If xi​= xj​ and yi…

Mur loves hash algorithm, and he sometimes encrypt another one's name, and call him with that encrypted value. For instance, he calls Kimura KMR, and calls Suzuki YJSNPI. One day he read a book about SHA-256,which can transit a string into just 256 b…

链接 https://nanti.jisuanke.com/t/31456 参考题解  https://blog.csdn.net/ftx456789/article/details/82590044 #include <bits/stdc++.h> #define pb push_back #define mp make_pair #define fi first #define se second #define all(a) (a).begin(), (a).end() #define…

ACM-ICPC 2018 徐州赛区网络预赛 G. Trace (思维,贪心) Trace 问答问题反馈 只看题面 35.78% 1000ms 262144K There's a beach in the first quadrant. And from time to time, there are sea waves. A wave ( xx , yy ) means the wave is a rectangle whose vertexes are ( 00 , 00 ), ( xx ,…