题目链接:https://vjudge.net/problem/POJ-2478 Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 17753 Accepted: 7112 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b…
hdu1787,直接求欧拉函数 #include <iostream> #include <cstdio> using namespace std; int n; int phi(int n){ int ans=n; for(int i=2; i*i<=n; i++) if(n%i==0){ ans -= ans / i; while(n%i==0) n /= i; } if(n>1) ans -= ans / n; return ans; } int main(){…
Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in increasing order. Th…
链接: https://vjudge.net/problem/POJ-2478 题意: The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in increasing order. The first few are F2 = {1/2} F3 =…
Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 14291 Accepted: 5647 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b)…
题目大意 直接看原文吧.... The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in increasing order. The first few areF2 = {1/2}F3 = {1/3, 1/2, 2/3}F4 = {1/4, 1/3…
Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 18507 Accepted: 7429 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b)…
题目链接: Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 14230 Accepted: 5624 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd…
A - Farey Sequence Time Limit:1000MS Memory Limit:65536KB 64bit IO Format:%I64d & %I64u Submit Status Practice POJ 2478 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 &l…
The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in increasing order. The first few are F2 = {1/2} F3 = {1/3, 1/2, 2/3} F4 = {1/4, 1/3, 1/2, 2/3, 3…
题目链接:http://poj.org/problem?id=2478 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in increasing order. The first few are F2 = {1/2}…
一.题目 The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in increasing order. The first few are F2 = {1/2} F3 = {1/3, 1/2, 2/3} F4 = {1/4, 1/3, 1/2, 2…
洛谷题目传送门 分数其实就是一个幌子,实际上就是求互质数对的个数(除开一个特例\((1,1)\)).因为保证了\(a<b\),所以我们把要求的东西拆开看,不就是\(\sum_{i=2}^n\phi(i)\)吗? 关于通过筛素数线性求欧拉函数的一点思路总结在蒟蒻的blog里 剩下的就是记一个前缀和了. #include<cstdio> #define R register const int N=1000001; int pr[N],phi[N]; long long ans[N]; bo…
Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 16927 Accepted: 6764 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b)…
Farey Sequence Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 15242 Accepted: 6054 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b)…
题目链接:https://vjudge.net/problem/POJ-2478 题意:给定n,输出集合中元素的数量,集合中的元素为最简小于1的分数,分子分母均属于[1,n-1]. 思路:理清题意后就是输入n,输出[1,n]区间所有数的欧拉函数之和.要注意结果会超出int范围. AC代码: #include<cstdio> using namespace std; typedef long long LL; ; int eu[maxn],n; LL sum[maxn]; void eular(…
题意:给定一个数 n,问你0<= a <=n, 0 <= b <= n,有多少个不同的最简分数. 析:这是一个欧拉函数题,由于当时背不过模板,又不让看书,我就暴力了一下,竟然AC了,才2s,题目是给了3s,很明显是由前面递推,前面成立的,后面的也成立, 只要判定第 i 个有几个,再加前 i-1 个就好,第 i 个就是判断与第 i 个互质的数有多少,这就是欧拉函数了. 代码如下: 这是欧拉函数的. #pragma comment(linker, "/STACK:102400…
Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 15023 Accepted: 5962 Description The Farey Sequence Fn for any integer n with n >= 2 is the set of irreducible rational numbers a/b with 0 < a < b <= n and gcd(a,b) = 1 arranged in…
