HDU6030 Happy Necklace 推导或者可以找规律有公式:\(f[n] = f[n-1] + f[n-3]\) . 构造矩阵乘法: \[ \begin{pmatrix} f_i \\ f_{i-1} \\ f_{i-2} \end{pmatrix} = \begin{pmatrix} 1 & 0 & 1 \\ 1 & 0 & 0 \\ 0 & 1 & 0 \end{pmatrix}\begin{pmatrix} f_{i-1} \\ f_{i-…
从今天开始就有各站网络赛了 今天是ccpc全国赛的网络赛 希望一切顺利 可以去一次吉大 希望还能去一次大连 题意: 很明确是让你求Sn=[a+sqrt(b)^n]%m 思路: 一开始以为是水题 暴力了一发没过 上网看了一下才知道是快速幂 而且特征方程的推导简直精妙 尤其是共轭相抵消的构造 真的是太看能力了 (下图转自某大神博客) 特征方程是C^2=-2*a*C+(a*a-b) 然后用快速幂求解 临时学了下矩阵快速幂 从这道题能看出来 弄ACM真的要数学好 这不是学校认知的高数 线代 概率分数 而…
传送门 由于没有考虑n<=1的情况T了很久啊. 这题很有意思啊. 考试的时候根本不会,骗了30分走人. 实际上变一个形就可以了. 推导过程有点繁杂. 直接粘题解上的请谅解. 不得不说这个推导很妙. 然后就可以矩阵快速幂优化了. 代码: #include<bits/stdc++.h> #define ll long long using namespace std; ll a,b,n,mod; struct Matrix{ ll a[3][3]; Matrix(){a[0][0]=a[0]…
题目链接  Broken Clock   中文题面链接 令$cos(xα) = f(x)$ 根据三角函数变换公式有 $f(x) = \frac{2d}{l} f(x-1) - f(x-2)$ 我们现在要求的是$l * f(t)$,把$f(t)$表示成$\frac{p}{q}$的形式 令$f(x) = \frac{g(x)}{l^{x}}$,那么$g(x) = p, l^{x} = q$ $\frac{g(x)}{l^{x}} = \frac{2d}{l} * \frac{g(x-1)}{l^{x…
http://www.lightoj.com/volume_showproblem.php?problem=1070 思路:\({(a+b)}^n =(a+b){(a+b)}^{n-1} \) \((ab)C_{n}^{r}a^{n-r}b{r} = C_{n+2}^{r}a^{n-r+2}b{r} - a^{n+2} - b^{n+2} \) 综上\( f(n) = (a+b)f(n-1)-(ab)f(n-2) \) /** @Date : 2016-12-19-19.53 * @Author…
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…
Happy Necklace 前天个人赛规律都找出来了,n的范围是\(10^{18}\),我一想GG,肯定是矩阵快速幂,然后就放弃了. 昨天学了一下矩阵快速幂. 题意 现在小Q要为他的女朋友一个有n个宝石的好的项链(直线),定义好的项链为:如果任意素数长的子串中蓝宝石的数量不小于红宝石的数量就是好的.小Q可以买多少种好的项链呢? 思路 n这么大,绝对是规律题. 先简单分析一下,其实对于好项链的定义可以化简为任意长度为3的子串中至少有两个蓝宝石,然后打表. #include<bits/stdc++…
题目链接 :http://acm.hdu.edu.cn/showproblem.php?pid=6030 Problem Description 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,…
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…
Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 222    Accepted Submission(s): 91 Problem Description Little Q wants to buy a necklace for his girlfriend. Necklaces are single strings compose…