题目:http://poj.org/problem?id=2262 水水更健康~ 代码如下: #include<iostream> #include<cstdio> #include<cstring> using namespace std; int const maxn=1e6; ],cnt; ]; void init() { ;i<=maxn;i++) { if(!vis[i])pri[++cnt]=i; ;j<=cnt&&i*pri[j…

poj2262 Goldbach's Conjecture 用欧拉筛把素数筛出来,再枚举一下. #include<iostream> #include<cstdio> #include<cstring> #define re register using namespace std; #define N 1000001 int n,v[N],pri[N],cct; bool is[N]; int main(){ ;i<N;++i){ ; ;j<=cct;++…

Goldbach's Conjecture Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 48161   Accepted: 18300 Description In 1742, Christian Goldbach, a German amateur mathematician, sent a letter to Leonhard Euler in which he made the following conject…

题目:http://poj.org/problem?id=2262 大水题的筛质数. #include<iostream> #include<cstdio> #include<cstring> using namespace std; const int N=1e6; ],cnt; ]; void init() { ;i<=N;i++) { if(!vis[i])pri[++cnt]=i; ;j<=cnt&&(long long)i*pri[…

一.Description In 1742, Christian Goldbach, a German amateur mathematician, sent a letter to Leonhard Euler in which he made the following conjecture: Every even number greater than 4 can be written as the sum of two odd prime numbers. For example: 8…

In 1742, Christian Goldbach, a German amateur mathematician, sent a letter to Leonhard Euler in which he made the following conjecture: Every even number greater than 4 can be written as the sum of two odd prime numbers. For example: 8 = 3 + 5. Both…

题目链接:https://cn.vjudge.net/problem/LightOJ-1259 题意 给一个整数n,问有多少对素数a和b,使得a+b=n 思路 素数筛 埃氏筛O(nloglogn),这个完全够用,当n=3.5e7时将近一秒(1e8次操作) 欧拉筛O(n) 考虑数论专题过完了就写个模版专题 提交过程 AC 代码 #include <cstdio> #include <cstring> using namespace std; const int maxn=1e7+20…

题意:给出n,问满足a+b=n且a,b都为素数的有多少对 将素数打表,再枚举 #include<iostream> #include<cstdio> #include<cstring> #include <cmath> #include<stack> #include<vector> #include<map> #include<algorithm> #define mod=1e9+7; using names…

Goldbach`s Conjecture Goldbach's conjecture is one of the oldest unsolved problems in number theory and in all of mathematics. It states: Every even integer, greater than 2, can be expressed as the sum of two primes [1]. Now your task is to check whe…

http://poj.org/problem?id=2262 Goldbach's Conjecture Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 34323   Accepted: 13169 Description In 1742, Christian Goldbach, a German amateur mathematician, sent a letter to Leonhard Euler in whic…