题目链接:http://172.16.200.33/JudgeOnline/problem.php?id=1002 题意:给你两个四位数的素数,求最少经过多少步的变化能够从一个素数变到另一个素数.在变得过程中,要求都是素数,而且每个新的数和原来的数只有一位不一样. 思路:因为是四位的素数,所以先对素数打表,然后BFS,每次进入队列的是八个只有一个数字不同的四位数,并且还要是素数就入队 #include <cstdio> #include <queue> #include <c…

Constructing Roads Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 20927    Accepted Submission(s): 8023 Problem Description There are N villages, which are numbered from 1 to N, and you should…

输入一个数,判断其是否为素数: 本题有多组测试样例. 输入规则如下: 第一行为一个整数,样例组数T: 第二至第t+1行每行都有一个整数a(a >= 2),表示需要处理的数: 如果是素数则输出“yes”,否则输出“no”,每个样例的输出占1行: 输入输出样例: 输入: 2 99 17 输出: no yes 就是判断素数问题,本来我是想用sqrt的,但是不知道为什么过不了,所以就用了\2,本来用前者是能够减少时间的,不过检测数据小,都没有关系 #include<stdio.h> int ma…

I am going to my home. There are many cities and many bi-directional roads between them. The cities are numbered from 0 to n-1 and each road has a cost. There are m roads. You are given the number of my city t where I belong. Now from each city you h…

Prime Path Time Limit: 1000MS   Memory Limit: 65536KB   64bit IO Format: %I64d & %I64u Submit Status 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 the fo…

前言 依旧是白嫖账号,只打了一些题/kk 正题 1002 Buying Snacks 题目大意 \(n\)个物品,每个可以买一次也可以不买,如果买需要选择\(1/2\)块钱的,然后也可以相邻两个一起买并且减少一块的花销,求恰好用掉\(m\)块钱的方案. \(1\leq n\leq 10^9,1\leq m\leq 20000,1\leq T\leq 5\) 解题思路 设\(f_{i,j}\)表示\(i\)个物品花\(j\)块钱的方案那么有 \[f_{i,j}=f_{i-1,j}+f_{i-1,j…

Description: Count the number of prime numbers less than a non-negative number, n click to show more hints. Credits:Special thanks to @mithmatt for adding this problem and creating all test cases. 求n以内的所有素数,以前看过的一道题目,通过将所有非素数标记出来,再找出素数,代码如下: public i…

Peter wants to generate some prime numbers for his cryptosystem. Help him! Your task is to generate all prime numbers between two given numbers! Input The input begins with the number t of test cases in a single line (t<=10). In each of the next t li…

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…

传送门 Description A ring is composed of n (even number) circles as shown in diagram. Put natural numbers 1, 2, . . . , n into each circle separately, and the sum of numbers in two adjacent circles should be a prime. Note: the number of first circle sho…