hdu2138 How many prime numbers #include <bits/stdc++.h> using namespace std; typedef long long ll; ll prime[] = {,,,,}; ll qmul(ll a, ll b, ll mod) { ll res = ; while (b) { ) res = (res+a)%mod; a = (a+a)%mod; b >>= ; } return res; } ll qpow(ll…

传送门 miller−rabbinmiller-rabbinmiller−rabbin素数测试的模板题. 实际上miller−rabinmiller-rabinmiller−rabin就是利用费马小定理和二次探测的性质来进行判断的. 注意要多带几个素数进去判断(听大神说只要取遍了50以内的质数就可以判断intintint范围内的) 代码: #include<bits/stdc++.h> #define ri register int using namespace std; inline in…

来源: HDU 2007-11 Programming Contest_WarmUp 题目大意:素数判定. 思路: 事实上暴力判定也可以过,但我还是用了Miller-Rabin算法. 核心思想:利用费马小定理,得到对于质数$p$,我们有$a^{p-1}\equiv 1(mod\ p)$或$a^p\equiv a(mod\ p)$. 反过来,满足条件的不一定是质数,但有很大概率是质数,因此我们只要多随机几个$a$来判定,出错的概率就非常低了. 求幂的运算可以使用Montgomery模幂算法. 注意…

Sum of Consecutive Prime Numbers Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 20050   Accepted: 10989 Description Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representatio…

题目链接: 传送门 Sum of Consecutive Prime Numbers Time Limit: 1000MS     Memory Limit: 65536K Description Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representations does a given positive intege…

Sieve of Eratosthenes (素数筛选算法) Given a number n, print all primes smaller than or equal to n. It is also given that n is a small number. For example, if n is 10, the output should be “2, 3, 5, 7″. If n is 20, the output should be “2, 3, 5, 7, 11, 13,…

Problem Description Give you a lot of positive integers, just to find out how many prime numbers there are. Input There are a lot of cases. In each case, there is an integer N representing the number of integers to find. Each integer won't exceed 32-…

题目链接:Codeforces 385C Bear and Prime Numbers 这题告诉我仅仅有询问没有更新通常是不用线段树的.或者说还有比线段树更简单的方法. 用一个sum数组记录前n项和,这个sum数组在打素数表时候就能够求出来,注意一点求素数的内层循环要改成i.不能再写成i + i或者i * i了.原因想想就明确了. 这学期最后一场比赛也结束了,结果不非常惬意但也还好. 总的来说这学收获还是蛮多的. 近期可能就不再做ACM了吧,可能要复习CET6了吧,可能要复习期末考试的内容了吧.…

POJ2739 Sum of Consecutive Prime Numbers 题目大意:给出一个整数,如果有一段连续的素数之和等于该数,即满足要求,求出这种连续的素数的个数 水题:艾氏筛法打表+尺取法区间推进,0ms水过(注意循环的终止条件) #include <cstdio> #include <cstdlib> #include <cstring> #include <cmath> #include <ctime> #include &l…

Alexandra and Prime Numbers Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1658    Accepted Submission(s): 565 Problem Description Alexandra has a little brother. He is new to programming. One…