Dillonh的博客

欧拉函数欧拉函数的定义：1~N中与N互质的数的个数被称为欧拉函数，我们用phi[i]来记录与i互质的数的个数。根据算数基本定理（唯一分解定理），即N可以分解成N=p1^c1*p2^c2*…pm^cm，其中pi为质数可以推出phi[N]=N * (p1 - 1) / p1 * (p2 - 1) / p2*…(pm - 1) / pm。欧拉函数的部分性质：phi[n] = phi[n / p] * (...

传送门题目fn=c2∗n−6fn−1fn−2fn−3\begin{aligned}&f_n=c^{2*n-6}f_{n-1}f_{n-2}f_{n-3}&\\\end{aligned}​fn​=c2∗n−6fn−1​fn−2​fn−3​​​思路我们通过迭代发现fnf_nfn​其实就是由cx1,f1x2,f2x3,f3x4c^{x_1},f_1^{x_...

题目链接传送门题面思路：我们先将公式进行化简：∏i=1n∏i=1n∏i=1nmgcd(i,j)[k∣gcd(i,j)]=m∑i=1n∑j=1n∑k=1ngcd(i,j)[k∣gcd(i,j)]\begin{aligned}&\prod_{i=1}^{n}\prod_{i=1}^{n}\prod_{i=1}^{n}m^{gcd(i,j)[k|gcd(i,j)]}&a...

#include <bits/stdc++.h>using namespace std;typedef long long LL;const int maxn = 3e6 + 3;int t, n, cnt;bool v[maxn];short mu[maxn];int isp[maxn], phi[maxn];LL sum1[maxn];int sum2[maxn...

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=6287题目：口算训练Time Limit: 8000/4000 MS (Java/Others)    Memory Limit: 512000/512000 K (Java/Others)Total Submission(s): 177    Accepted Submission(s): 41Pro...

题目链接：http://acm.fzu.edu.cn/problem.php?pid=1759题目：Problem DescriptionGiven A,B,C, You should quickly calculate the result of A^B mod C. (1&lt;=A,C&lt;=1000000000,1&lt;=B&lt;=10^1000000). InputThere ar...

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2842题目：Problem DescriptionDumbear likes to play the Chinese Rings (Baguenaudier). It’s a game played with nine rings on a bar. The rules of this game are...

题目链接：http://codeforces.com/problemset/problem/185/A题目：Dwarfs have planted a very interesting plant, which is a triangle directed "upwards". This plant has an amusing feature. After one year a triangle...

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1575题目：Problem DescriptionA为一个方阵，则Tr A表示A的迹（就是主对角线上各项的和），现要求Tr(A^k)%9973。  Input数据的第一行是一个T，表示有T组数据。每组数据的第一行有n(2 &lt;= n &lt;= 10)和k(2 &lt;= k &lt; 10^9)两...

题目链接：https://www.nowcoder.com/acm/contest/105/G思路：这题一看数据范围就知道是个矩阵快速幂，通过构造矩阵知我们需要的转移矩阵为下图形式，不过需要特判1然后输出的是n-1的结果哦，因为这个我本题WA了==！矩阵快速幂最难得就是构造矩阵，当矩阵构造出来之后基本上就好做了~代码实现如下：#include &lt;cstdio&gt;#include &lt...

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=5407题目：Problem DescriptionCRB has N different candies. He is going to eat K candies.He wonders how many combinations he can select.Can you answer his que...

题目链接：http://acm.csu.edu.cn/csuoj/problemset/problem?pid=2021DescriptionEverybody loves big numbers (if you do not, you might want to stop reading at this point). There are many ways of constructing re...

题目链接：http://poj.org/problem?id=2478DescriptionThe Farey Sequence Fn for any integer n with n &gt;= 2 is the set of irreducible rational numbers a/b with 0 &lt; a &lt; b &lt;= n and gcd(a,b) = 1 arrang...

题目链接传送门题面题意给你n,kn,kn,k，要你求∑i=1nik\sum\limits_{i=1}^{n}i^ki=1∑n​ik的值。思路根据数学知识或者说题目提示可知∑i=1nik\sum\limits_{i=1}^{n}i^ki=1∑n​ik可以被一个k+1k+1k+1次多项式表示。由拉格朗日插值法(推荐学习博客)的公式：L(x)=l(x)∑i=1k+2yiwix−xi,其中...