HDU 1397 Goldbach's Conjecture【素数打表】

【HDU 1397 Goldbach's Conjecture【素数打表】】的更多相关文章

HDU 1397 Goldbach's Conjecture【素数打表】

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…

LightOJ 1259 Goldbach`s Conjecture 素数打表

题目大意:求讲一个整数n分解为两个素数的方案数. 题目思路:素数打表,后遍历 1-n/2,寻找方案数,需要注意的是:C/C++中 bool类型占用一个字节,int类型占用4个字节,在素数打表中采用bool类型可以节约不少内存. #include<iostream> #include<algorithm> #include<cstring> #include<vector> #include<stdio.h> #include<queue&g…

HDU 1397 Goldbach's Conjecture(二分，查找素数)

题目意思很简单,就是找n=p1+p2的种类数,具体看题目吧. 次重点是查找一定范围内的素数: 重点是用二分查找,不然会超时!!! #include<stdio.h> #include<string.h> int main() { ],num,s,l,r,mid; a[]=;s=; ;i<;i=i+)//这里是打出素数 { f=; ;j<s;j++) { if(a[j]*a[j]>i) break; ) { f=; break; } } ) a[s++]=i; }…

HDOJ 1397 Goldbach's Conjecture(快速筛选素数法)

Problem Description Goldbach's Conjecture: For any even number n greater than or equal to 4, there exists at least one pair of prime numbers p1 and p2 such that n = p1 + p2. This conjecture has not been proved nor refused yet. No one is sure whether…

POJ 2262 Goldbach's Conjecture （打表）

题目链接: https://cn.vjudge.net/problem/POJ-2262 题目描述: 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 t…

poj 2262 Goldbach's Conjecture(素数筛选法)

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…

POJ 2262 Goldbach's Conjecture(素数相关)

POJ 2262 Goldbach's Conjecture(素数相关) http://poj.org/problem?id=2262 题意: 给你一个[6,1000000]范围内的偶数,要你将它表示成两个素数相加和的形式.假设存在多组解,请输出两个素数差值最大的解. 分析: 首先我们用素数筛选法求出100W以内的全部素数. 筛选法求素数可见: http://blog.csdn.net/u013480600/article/details/41120083 对于给定的数X,假设存在素数a+素数b…