Prime Cuts Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 10610   Accepted: 4046 Description A prime number is a counting number (1, 2, 3, ...) that is evenly divisible only by 1 and itself. In this problem you are to write a program th…

ZOJ:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemId=312 POJ:http://poj.org/problem?id=1595 题目大意: 给你两个数n和c,如果1~n(包括1和n)之间的素数个数为偶数个,则输出中间c*2个素数否则输出中间c*2-1个素数. 思路: 呀呀呀,玩了一天了,A道水题洗洗睡吧. 直接筛选素数打表. 注意c比1~n的个数大的情况要把1~n中所以素数输出. OK,然后这题1也算素数.. #incl…

何为"打表"呢,说得简单点就是: 有时候与其重复运行同样的算法得出答案,还不如直接用算法把这组数据所有可能的答案都枚举出来存到一个足够大的容器中去-例如数组(打表),然后再输入数据的时候,直接遍历容器,检索这个数据是否有题意要求的结果. 举一个几乎所有程序员都知道的简单例子= =: 求素数(POJ 1595)-Prime cuts 这一题大意是给出 多组N(1~1000)和C,让你从N内素数的中间项向外扩展C个素数,比如给出7 1,素数有5个(注意此题出题人坑爹得让1作为"素…

#include <iostream> #define N 10010 using namespace std; int a[N],b[N]; int prime(int a) { int i; for(i=2;i*i<=a;i++) if(a%i==0) return 1; return 0; } int main() { int i,j,t,m,x,h,g; while(cin>>t>>x){ h=t;g=x; int k=1; for(m=t;m>1;…

A prime number is a counting number (1, 2, 3, ...) that is evenly divisible only by 1 and itself. In this problem you are to write a program that will cut some number of prime numbers from the list of prime numbers between (and including) 1 and N. Yo…

  POJ 3126  Prime Path Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 16204   Accepted: 9153 Description The ministers of the cabinet were quite upset by the message from the Chief of Security stating that they would all have to change…

题目链接:poj 2689 Prime Distance 题意: 给你一个很大的区间(区间差不超过100w),让你找出这个区间的相邻最大和最小的两对素数 题解: 正向去找这个区间的素数会超时,我们考虑逆向思维: 我们先用线性筛 筛出前50000的素数,在int范围内的区间的合数的因子都在我们之前筛出来了, 然后我们就把这个区间的合数标记出来,剩下的就是素数了. 标记合数也是用全部的素数去筛一下,这样就能快速的标记这个区间的合数,然后在暴力枚举一下这个区间,更新一下答案. #include<cst…

POJ 3126 Prime Path(素数路径) Time Limit: 1000MS    Memory Limit: 65536K Description - 题目描述 The ministers of the cabinet were quite upset by the message from the Chief of Security stating that they would all have to change the four-digit room numbers on…

POJ 1811 Prime Test Time Limit: 6000MS   Memory Limit: 65536K Total Submissions: 32534   Accepted: 8557 Case Time Limit: 4000MS Description Given a big integer number, you are required to find out whether it's a prime number. Input The first line con…

Prime Cuts Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 9339   Accepted: 3562 Description A prime number is a counting number (1, 2, 3, ...) that is evenly divisible only by 1 and itself. In this problem you are to write a program tha…

Prime Cuts Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 11961   Accepted: 4553 Description A prime number is a counting number (1, 2, 3, ...) that is evenly divisible only by 1 and itself. In this problem you are to write a program th…

POJ 3518 Prime Gap(素数) id=3518">http://poj.org/problem? id=3518 题意: 给你一个数.假设该数是素数就输出0. 否则输出比这个数大的素数与比这个数小的素数的差值. 分析: 明显本题先要用筛选法求出130W(个素数)以内的全部素数. 然后推断给的数是否是素数就可以. 假设不是素数.那么就找出它在素数素组内的上界和下界,输出两个素数的差值就可以. 筛选法求素数可见: http://blog.csdn.net/u013480600/a…

题目传送门 /* 题意:从一个数到另外一个数,每次改变一个数字,且每次是素数 BFS:先预处理1000到9999的素数,简单BFS一下.我没输出Impossible都AC,数据有点弱 */ /************************************************ Author :Running_Time Created Time :2015-8-2 15:46:57 File Name :POJ_3126.cpp ****************************…

[POJ]P3126 Prime Path Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 35230   Accepted: 18966 Description The ministers of the cabinet were quite upset by the message from the Chief of Security stating that they would all have to change…

Prime Test Time Limit: 6000MS   Memory Limit: 65536K Total Submissions: 29046   Accepted: 7342 Case Time Limit: 4000MS Description Given a big integer number, you are required to find out whether it's a prime number. Input The first line contains the…

题目地址:http://poj.org/problem?id=2689 题意:给你一个不超过1000000的区间L-R,要你求出区间内相邻素数差的最大最小值,输出相邻素数. AC代码: #include <iostream> #include <cstdio> #include <cstring> #include <string> #include <cstdlib> #include <cmath> #include <ve…

题目:http://poj.org/problem?id=3126 题意:给定两个四位数,求从前一个数变到后一个数最少需要几步,改变的原则是每次只能改变某一位上的一个数,而且每次改变得到的必须是一个素数: #include <iostream> #include<cstdio> #include<cstring> #include<cstdlib> #include<stack> #include<queue> #include<…

题目: http://poj.org/problem?id=3126 困得不行了,没想到敲完一遍直接就A了,16ms,debug环节都没进行.人品啊. #include <stdio.h> #include <string.h> #include <queue> using namespace std; ]; ]; int s, t; void prime_init() { memset(prime, , sizeof(prime)); prime[] = ; ; i…

题目链接:http://poj.org/problem?id=3126 Prime Path Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 32036   Accepted: 17373 Description The ministers of the cabinet were quite upset by the message from the Chief of Security stating that they…

题目链接:http://poj.org/problem?id=3126 题意: 给定两个四位素数 $a,b$,要求把 $a$ 变换到 $b$.变换的过程每次只能改动一个数,要保证每次变换出来的数都是一个没有前导零的四位素数. 要求每步得到的素数都不能重复,求从 $a$ 到 $b$ 最少需要变换多少步:如果无法达到则输出Impossible. 题解: 在BFS之前先用线性筛筛出 $10000$ 以内的素数,方便后面判断是否为素数. 剩下的就是从 $a$ 为起点,入队并标记已经出现过.每次队列非空就…

题目链接:http://poj.org/problem?id=2689 Time Limit: 1000MS Memory Limit: 65536K Description The branch of mathematics called number theory is about properties of numbers. One of the areas that has captured the interest of number theoreticians for thousan…

题目链接 Description Given a big integer number, you are required to find out whether it's a prime number. Input The first line contains the number of test cases T (1 <= T <= 20 ), then the following T lines each contains an integer number N (2 <= N…

链接:Truck History - POJ 1789 - Virtual Judge  https://vjudge.net/problem/POJ-1789 题意:先给出一个n,代表接下来字符串的个数,接下来n个字符串,每个字符串长度为7,没有完全相同的字符串,字符串之间的距离是两个字符串里不同字符的个数(相同位置两两对比),然后求出从某个点到其他点距离和的最小值(分子一直是1,Q越小,1/Q越大),其实就是叫我们求出最小生成树,先字符串两两相比建图,然后求最小生成树. #include<i…

Prime Test Time Limit: 6000MS   Memory Limit: 65536K Total Submissions: 27129   Accepted: 6713 Case Time Limit: 4000MS Description Given a big integer number, you are required to find out whether it's a prime number. Input The first line contains the…

Prime Path POJ - 3126 题意: 给出两个四位素数 a , b.然后从a开始,每次可以改变四位中的一位数字,变成 c,c 可以接着变,直到变成b为止.要求 c 必须是素数.求变换次数的最小值.(a,b,c都是四位数字,输入时没有前导零) 分析: 每次改变可以获得一个四位数c,然后如果c是素数并且之前没有出现过,那么我们把它放入队列即可. int f[10001]; int v[10001]; void init()//素数筛 { memset(f,0,sizeof f); fo…

题目传送门 题意:素性测试和大整数分解, N (2 <= N < 254). 分析:没啥好讲的,套个模板,POJ上C++提交 收获:写完这题得到模板 代码: /************************************************ * Author :Running_Time * Created Time :2015-8-28 13:02:38 * File Name :POJ_1811.cpp ************************************…

http://poj.org/problem?id=2689 题意:给出一个大区间[L,U],分别求出该区间内连续的相差最小和相差最大的素数对. 由于L<U<=2147483647,直接筛素数是不行的,数组就开不了.可是能够依据素数筛的原理.我们先筛出sqrt(2147483647)以内的素数,然后拿这些素数去筛[L,U]之间的素数,即两次素数筛.可是L,U还是非常大,但U-L<=1000000,所以进行区间平移,将[L,U]平移为[0,U-L],就能用数组放得下. #include &…

给定两个四位素数a  b,要求把a变换到b 变换的过程要保证  每次变换出来的数都是一个 四位素数,而且当前这步的变换所得的素数  与  前一步得到的素数  只能有一个位不同,而且每步得到的素数都不能重复. 求从a到b最少需要的变换次数.无法变换则输出Impossible   输入: 第一行 是一个数T 表示下面有T个测试数据 下面T行  每行两个数a b 解题思路:每次变换一次,个十百千,四个位置上的数每个从0-9循环一边一共需要4 * 10 = 40次循环  剪枝之后就没多少了 所以直接暴力…

题目链接: 传送门 Prime Land Time Limit: 1000MS     Memory Limit: 10000K Description Everybody in the Prime Land is using a prime base number system. In this system, each positive integer x is represented as follows: Let {pi}i=0,1,2,... denote the increasing…

Prime Distance Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 12512   Accepted: 3340 Description The branch of mathematics called number theory is about properties of numbers. One of the areas that has captured the interest of number th…