传送门:http://acm.tzc.edu.cn/acmhome/problemdetail.do?&method=showdetail&id=3151 时间限制(普通/Java):1000MS/3000MS     内存限制:65536KByte 描述 H1N1 like to solve acm problems.But they are very busy, one day they meet a problem. Given three intergers a,b,c, the…

https://codeforces.com/contest/1106/problem/F 题意 数列公式为\(f_i=(f^{b_1}_{i-1}*f^{b_2}_{i-2}*...*f^{b_k}_{i-k})\)mod\(P\),给出\(f_{1}...f_{k-1}\)和\(f_{n}\),求\(f_{k}\),其中\(P\)等于998244353 题解 3是998244353的离散对数,所以\(f^{b_1}_{i-1} \equiv 3^{h_i*b_1}(modP)\),怎么求离散…

Sum Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 3245    Accepted Submission(s): 1332 Problem Description   Sample Input 2   Sample Output 2 Hint 1. For N = 2, S(1) = S(2) = 1. 2. The input…

题目链接:http://acm.fzu.edu.cn/problem.php?pid=1759 欧拉降幂是用来干啥的?例如一个问题AB mod c,当B特别大的时候int或者longlong装不下的时候需要对B mod 一个数并且不改变最终的答案,这就可以将使用欧拉降幂公式来进行计算. 公式:AB mod C  == AB%φ(C) + φ(C) mod C (其实φ(c)是c的欧拉函数值),这样就是欧拉函数的使用. #include <stdio.h> #include <cstrin…

Sum Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 3980    Accepted Submission(s): 1620 Problem Description   Sample Input 2   Sample Output 2 Hint 1. For N = 2, S(1) = S(2) = 1. 2. The input…

2019-ACM-ICPC-南昌区网络赛-H. The Nth Item-特征根法求通项公式+二次剩余+欧拉降幂 [Problem Description] ​ 已知\(f(n)=3\cdot f(n-1)+2\cdot f(n-2),(n\ge 2)\),求\(f(n)\pmod {998244353}\). [Solution] ​ 利用特征根法求得通项公式为\(a_n=\frac{\sqrt{17}}{17}\cdot\Bigg(\Big(\frac{3+\sqrt{17}}{2} \Bi…

题意:https://codeforc.es/contest/906/problem/D 计算区间的: ai ^ ai+1 ^ ai+2.......ar . 思路: 广义欧拉降幂: 注意是自下而上递归使用欧拉降幂,比如求:a^b^c == a^(b^c%phi(mod)+?) == a^(b^(c%phi(phi(mod))+?+?) 而不是:a^b^c == a^b^(c%phi(mod)+?) == a^(b^(c%phi(mod)+?)%phi(mod)+?)  这样本身就是不对的,次方…

题目链接:http://codeforces.com/contest/906/problem/D 题目大意:给定n个整数w[1],w[2],……,w[n],和一个数m,然后有q个询问,每个询问给出一个l,r,求w[l]^w[l+1]^w[l+2]……w[r]  %m  ,即a[l]到a[r]的幂次方 解题思路:利用欧拉降幂公式 第一个要求a和p互质,第2个和第3个为广义欧拉降幂,不要求a和p互质,用在这题刚好. 因为有两种情况,所以我们需要自定义一下降幂取模公式. 我们对整个区间进行递归处理,每…

Exponial 题目 http://exam.upc.edu.cn/problem.php?cid=1512&pid=4 欧拉降幂定理:当b>phi(p)时,有a^b%p = a^(b%phi(p)+phi(p))%p 这题做的难受....看到题目我就猜到肯定用到欧拉降幂,然后就毫无目的地找规律.然后发现不同地取欧拉函数会变成0,然后内心毫无波动.....可能不怎么会递归 思路:当n>=6时,欧拉降幂定理一定适用,因为f(5)>1e9,也就是一定有欧拉降幂定理的b>phi…

Nastya received a gift on New Year - a magic wardrobe. It is magic because in the end of each month the number of dresses in it doubles (i.e. the number of dresses becomes twice as large as it is in the beginning of the month). Unfortunately, right a…