http://www.lightoj.com/volume_showproblem.php?problem=1244 题意:给出六种积木,不能旋转,翻转,问填充2XN的格子有几种方法.\(N <= 10^9 \) 思路:首先手写出前几项,猜出递推式,如果真有比赛出这种题,又不能上网进工具站查是吧?N比较大显然用矩阵快速幂优化一下 /** @Date : 2016-12-18-22.44 * @Author : Lweleth (SoungEarlf@gmail.com) * @Link : ht…

Recursive sequence Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 249    Accepted Submission(s): 140 Problem Description Farmer John likes to play mathematics games with his N cows. Recently, t…

HDU 2604 Queuing (递推+矩阵快速幂) 这位作者讲的不错,可以看看他的 #include <cstdio> #include <iostream> #include <algorithm> #include <cmath> #include <cstring> using namespace std; const int N = 5; int msize, Mod; struct Mat { int mat[N][N]; }; M…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2842 题目大意:棒子上套环.第i个环能拿下的条件是:第i-1个环在棒子上,前i-2个环不在棒子上.每个环可以取下或放上,cost=1.求最小cost.MOD 200907. 解题思路: 递推公式 题目意思非常无聊,感觉是YY的. 设$dp[i]$为取第i个环时的总cost. $dp[1]=1$,$dp[2]=2$,前两个环取下是没有条件要求的. 从i=3开始,由于条件对最后的环限制最大,所以从最后一…

题目链接 F[1] = a, F[2] = b, F[i] = 2 * F[i-2] + F[i-1] + i ^ 4, (i >= 3) 现在要求F[N] 类似于斐波那契数列的递推式子吧, 但是N最大能到int的最大值, 直接循环推解不了 所以就得用矩阵快速幂咯 现在就看转移矩阵长什么样了 Mi表示要求的矩阵 转移矩阵用A表示 A * Mi = Mi+1 矩阵Mi里面至少得有 F[i-1] F[i-2] i ^ 4 Mi+1就相应的有 F[i] F[i-1] (i+1)^4 (i+1)^4 =…

传送门:点我 Little Q wants to buy a necklace for his girlfriend. Necklaces are single strings composed of multiple red and blue beads. Little Q desperately wants to impress his girlfriend, he knows that she will like the necklace only if for every prime l…

题目链接 我们可以把棱柱拆成有\(n\)条高的矩形,尝试递推. 在计算的过程中,第\(i\)列(\(i\neq n\))只与\(i-1\)列有关,称\(i-1\)列的上面/下面为左上/左下,第\(i\)列的上面/下面为右上/右下. 我们可以发现,右上可选的颜色数与左上和右下是否同色有关,右下同理,那就记\(f[i][0/1][0/1]\)表示左上与右下是否同色,左下与右上是否同色. 但是第\(n\)列和第\(1\)列不能同色,最后怎么算答案? 不知道第\(n\)列状态算不了,所以我们还要记第\(…

传送门:Educational Codeforces Round 60 – D   题意: 给定N,M(n <1e18,m <= 100) 一个magic gem可以分裂成M个普通的gem,现在需要N个gem,可以选择一定的magic gem,指定每一个分裂或不分裂,问一共有多少种方案 两种分裂方案不同当且仅当magic gem的数量不同,或者分裂的magic gem的索引不同. 思路: 1.首先从dp的角度出发 设F(i)为最终需要i个gem的方案数,容易得到递推式: (总方案数 = 最右边…

Happy Necklace Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 1146    Accepted Submission(s): 491 Problem Description Little Q wants to buy a necklace for his girlfriend. Necklaces are single…

Problem Description Queues and Priority Queues are data structures which are known to most computer scientists. The Queue occurs often in our daily life. There are many people lined up at the lunch time.   Now we define that ‘f’ is short for female a…