题意:略. 思路:问题转化为1到N,他们的满足mu[d]!=0的因子d个数.  即1到N的因子的莫比乌斯系数平方和. (经验:累加符号是累加的个数,我们把常数提到前面,然后用杜教筛累加个数即可. https://www.cnblogs.com/clrs97/p/6012285.html 关键部分,perfectxx都给了注释的(感谢) http://www.perfectxxlowiq.com/2018/03/22/hdu5942-%E6%95%B0%E8%AE%BA/ #include<bit…

题意:\( g(k) = 2^{f(k)} \) ,求\( \sum_{i = 1}^{n} g(i) \),其中\( f(k)\)代表k的素因子个数. 思路:题目意思很简单,但是着重于推导和简化,这是数论题的一贯思路,其中g(k)的方程可以看出是求k的无平方因子的个数,那么题目就是求1~n的无平方因字数的和了. 首先我们可以从莫比乌斯函数入手. 从\( \mu(d) \)的性质有,当d为素数单次连积时\( \mu(d)=(-1)^k\),其余d不为1时\( \mu(d)=0\) 那么可知\(…

主题链接:http://acm.hdu.edu.cn/showproblem.php?pid=5055 Problem Description Recently, Bob has been thinking about a math problem. There are N Digits, each digit is between 0 and 9. You need to use this N Digits to constitute an Integer. This Integer need…

任意门:http://acm.hdu.edu.cn/showproblem.php?pid=1757 A Simple Math Problem Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 6621    Accepted Submission(s): 4071 Problem Description Lele now is thin…

A Simple Math Problem Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2441    Accepted Submission(s): 1415 Problem Description Lele now is thinking about a simple function f(x). If x < 10 f(x) =…

Jam's math problem Problem Description Jam has a math problem. He just learned factorization.He is trying to factorize ax^2+bx+c into the form of pqx^2+(qk+mp)x+km=(px+k)(qx+m).He could only solve the problem in which p,q,m,k are positive numbers.Ple…

题目 A Simple Math Problem 解析 矩阵快速幂模板题 构造矩阵 \[\begin{bmatrix}a_0&a_1&a_2&a_3&a_4&a_5&a_6&a_7&a_8&a_9\\ 1&0&0&0&0&0&0&0&0&0\\ 0&1&0&0&0&0&0&0&0&0\\ 0&…

A Simple Math Problem [题目链接]A Simple Math Problem [题目类型]矩阵快速幂 &题解: 这是一个模板题,也算是入门了吧. 推荐一个博客:点这里 跟着这个刷,应该就可以了 &代码: #include <cstdio> #include <iostream> #include <set> #include <cmath> #include <cstring> #include <al…

A Simple Math Problem Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1697    Accepted Submission(s): 959 Problem Description Lele now is thinking about a simple function f(x). If x < 10 f(x) =…

A Simple Math Problem Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1645    Accepted Submission(s): 468 Problem Description Given two positive integers a and b,find suitable X and Y to meet th…