题意:给出一个偶数(不论正负),求出两个素数a,b,能够满足 a-b=x,素数在1e6以内. 只要用筛选法打出素数表,枚举查询下就行了. 我用set储存素数,然后遍历set里面的元素,查询+x后是否还是素数. 注意,偶数有可能是负数,其实负数就是将它正数时的结果颠倒就行了. 代码: /* * Author: illuz <iilluzen[at]gmail.com> * Blog: http://blog.csdn.net/hcbbt * File: 10.cpp * Create Date:…

http://acm.hdu.edu.cn/showproblem.php?pid=4715 Difference Between Primes Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description All you know Goldbach conjecture.That is to say, Every even integer great…

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=4715 Difference Between Primes Description All you know Goldbach conjecture.That is to say, Every even integer greater than 2 can be expressed as the sum of two primes. Today, skywind present a new conje…

Difference Between Primes Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 860 Accepted Submission(s): 278 Problem Description All you know Goldbach conjecture.That is to say, Every even integer gr…

Difference Between Primes Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 528    Accepted Submission(s): 150 Problem Description All you know Goldbach conjecture.That is to say, Every even inte…

http://acm.hdu.edu.cn/showproblem.php?pid=4715 [code]: #include <iostream> #include <cstdio> #include <cstring> #include <cmath> using namespace std; #define N 1000151 ]; ]; ]; ]; ; int lowbit(int i) { return i&-i; } void add(i…

题意:按字母顺序排列成n型,简单的模拟题. 当字母排到z时从a开始重新排起. 代码: /* * Author: illuz <iilluzen[at]gmail.com> * Blog: http://blog.csdn.net/hcbbt * File: a.cpp * Create Date: 2013-09-08 12:31:36 * Descripton: simulate */ #include <cstdio> #define rep(i, n) for (int i…

题意:给出一个n*n的矩阵,旋转每一圈数字,求出对角线可能的最大值,以及转到最大时的最小距离. 只要分析每一层就可以了,本来想用地址传递二维数组,发现行不通,改了一下就行了. 这里有个坑,比如: 1 1 9 9 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 很明显最大的就是将一个9转到矩阵角,而这里更新最大值时很容易把另一种情况屏蔽掉,从而错过了更少步骤达到最大值的方法. 代码: /* * Author: illuz <iilluzen[at]gmail.com> * Blo…

Zhuge Liang's Password Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 59    Accepted Submission(s): 47 Problem Description In the ancient three kingdom period, Zhuge Liang was the most famous a…

与其说这是一次重温AC自动机+dp,倒不如说这是个坑,而且把队友给深坑了. 这个题目都没A得出来,我只觉得我以前的AC自动机的题目都白刷了——深坑啊. 题目的意思是给你两个串,每个串只含有R或者D,要求有多少种长为(n+m)的串(其中有n个R,m个D)同时含有这两个串作为子串.(我就不说题目描述了) 看完了题目我居然一开始用排列组合去做,搞了近一个小时,深坑队友啊. 其实正解是用AC自动机来dp出解的. 什么意思呢?把两个给定的串放到AC字典树上,并且弄好fail指针,变为tire图,构造好AC…