题意: 求出来区间[1,n]内与n互质的数的数量 题解: 典型的欧拉函数应用,具体见这里:Relatives POJ - 2407 欧拉函数 代码: 1 #include<stdio.h> 2 #include<string.h> 3 #include<iostream> 4 #include<algorithm> 5 #include<math.h> 6 using namespace std; 7 typedef long long ll;…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1286 欧拉函数:对正整数n,欧拉函数是求少于n的数中与n互质的数的数目: 素数(质数)指在一个大于1的自然数中,除了1和此整数自身外,没法被其他自然数整除的数. φ函数的值 通式:φ(x)=x(1-1/p1)(1-1/p2)(1-1/p3)(1-1/p4)…..(1-1/pn),其中p1, p2……pn为x的所有质因数,x是不为0的整数.   φ(1)=1(唯一和1互质的数(小于等于1)就是1本身)…

Problem - 1286 用容斥原理做的代码: #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> #include <vector> using namespace std; ; int last[N]; void pre() { last[] = ; ; i < N; i++) { if (!last[i]) { for (int…

这道题就是一道简单的欧拉函数模板题,需要注意的是,当(1,1)时只有一个,其他的都有一对.应该对欧拉函数做预处理,显然不会超时. #include<iostream> #include<string.h> #include<algorithm> #include<stdio.h> using namespace std; ;//最大范围 int phi[maxx]; void phi_table(){ ;i<=maxx;i++)phi[i]=; phi…

题目: The Euler function Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 166 Accepted Submission(s): 96   Problem Description The Euler function phi is an important kind of function in number theory…

题目链接:https://vjudge.net/problem/POJ-2407 题意:给出n,求0..n-1中与n互质的数的个数. 思路:欧拉函数板子题,先根据唯一分解定理求出n的所有质因数p1,p2,...,pn,然后根据Φ(m)=m*∏(1-1/pi)计算即可. AC代码: #include<cstdio> using namespace std; int n,ans; int main(){ while(scanf("%d",&n),n){ ans=n; ;…

Description has only two Sentences Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 1071    Accepted Submission(s): 323 Problem Description an = X*an-1 + Y and Y mod (X-1) = 0.Your task is to cal…

Relatives Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 11372   Accepted: 5544 Description Given n, a positive integer, how many positive integers less than n are relatively prime to n? Two integers a and b are relatively prime if ther…

原题链接,点击此处 欧拉函数:φ(N)表示对一个正整数N,欧拉函数是小于N且与N互质的数的个数 通式:φ(x) = x(1-1/p1)(1-1/p2)(1-1/p3)(1-1/p4)…..(1-1/pn) 其中p1, p2……pn为x的所有质因数,x是不为0的整数. 注意:将n分解为最简质因数,每种质因数只用一次. 比如 12 = 2*2*3,那么 φ(12) = 12 * (1-1/2) * (1-1/3) = 4(1,5,7,11) 若 n = p^k ( p为 质数 ),则 φ(n) =…

The Euler function Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5235    Accepted Submission(s): 2225 Problem Description The Euler function phi is an important kind of function in number theo…