欧拉函数. phi(n)表示比n小的与n互质的数的个数,比如 phi(1) = 1; phi(2) = 1; phi(3) = 2; phi(4) = 2; phi(5) = 4; 性质: 1. 如果p为质数,则phi(p) = p-1; 2. 如果p为质数并且a为正整数,则phi(p^a) = p^a - p^(a-1); 证明:p为质数,所以所有可以和p相乘小于p^a的数有p^a/p = p^(a-1)个,剩下的都与p^a互质. 3. phi(ab) = phi(a)*phi(b) 4. n…

The Euler function Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5028    Accepted Submission(s): 2123 Problem Description The Euler function phi is an important kind of function in number theo…

The Euler function Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description The Euler function phi is an important kind of function in number theory, (n) represents the amount of the numbers which are sm…

6322.Problem D. Euler Function 题意就是找欧拉函数为合数的第n个数是什么. 欧拉函数从1到50打个表,发现规律,然后勇敢的水一下就过了. 官方题解: 代码: //1004-欧拉函数水题 #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<cmath> using namespace std; typede…

Time Limit: 1000MS   Memory Limit: 32768KB   64bit IO Format: %I64d & %I64u Description The Euler function phi is an important kind of function in number theory, (n) represents the amount of the numbers which are smaller than n and coprime to n, and…

The Euler function Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 4507    Accepted Submission(s): 1872     Problem Description The Euler function phi is an important kind of function in number…

http://acm.hdu.edu.cn/showproblem.php?pid=2824 Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 7752    Accepted Submission(s): 3217 Problem Description The Euler function phi is an important kin…

The Euler functionTime Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 6018 Accepted Submission(s): 2539 Problem DescriptionThe Euler function phi is an important kind of function in number theory, (n)…

The Euler function Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 32768/32768K (Java/Other) Total Submission(s) : 39   Accepted Submission(s) : 19 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description The Euler function…

题目链接:hdu 2824 The Euler function 题意: 让你求一段区间的欧拉函数值. 题解: 直接上板子. 推导过程: 定义:对于正整数n,φ(n)是小于或等于n的正整数中,与n互质的数的数目. 例如:φ(8)=4,因为1,3,5,7均和8互质. 性质:1.若p是质数,φ(p)= p-1. 2.若n是质数p的k次幂,φ(n)=(p-1)*p^(k-1).因为除了p的倍数都与n互质 3.欧拉函数是积性函数,若m,n互质,φ(mn)= φ(m)φ(n). 根据这3条性质我们就可以推…