http://acm.hdu.edu.cn/showproblem.php?pid=1016 #include <iostream> using namespace std; int a[30],n,used[40]; int is_prime(int x) { for(int i=2;i<x; i++) if(x%i==0) return 0; return 1; } void dfs(int cur) { int i; if(cur==n && is_prime(a[…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 42600    Accepted Submission(s): 18885 Problem Description A ring is compose of n circles as shown in diagram. Put natural num…

HDOJ(HDU).1016 Prime Ring Problem (DFS) [从零开始DFS(3)] 从零开始DFS HDOJ.1342 Lotto [从零开始DFS(0)] - DFS思想与框架/双重DFS HDOJ.1010 Tempter of the Bone [从零开始DFS(1)] -DFS四向搜索/奇偶剪枝 HDOJ(HDU).1015 Safecracker [从零开始DFS(2)] -DFS四向搜索变种 HDOJ(HDU).1016 Prime Ring Problem (…

Prime Ring Problem HDU - 1016 A ring is compose of n circles as shown in diagram. Put natural number 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 should a…

one recursive approach to solve hdu 1016, list all permutations, solve N-Queens puzzle. reference: the video of stanford cs106b lecture 10 by Julie Zelenski https://www.youtube.com/watch?v=NdF1QDTRkck // hdu 1016, 795MS #include <cstdio> #include &l…

嗯... 题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1016 一道很典型的dfs+回溯: 根据题意首先进行初始化,即第一个位置为1,然后进行dfs,枚举2~n之间的每一个数,如果这个数没被使用并且它和环中上一个数形成素数环,那么就把它加入环中,打上标记,然后继续dfs,最后回溯.当环上的个数正好等于n并且第一个数和最后一个数也能组成素数,则输出,输出时注意格式,很严格! dfs这里还有一个剪枝: 只有n为偶数时才可能形成素数环!因为当n为奇数时…

很简单的深搜 只要看出来是深搜... 注意判断最后一点是否与加一为质数 #include<stdio.h> #include<string.h> #include<algorithm> #include<map> #include<math.h> using namespace std; int n; int ans[30]; bool vis[30]; bool ok[105]; void init()///素数打表 { memset(ok,t…

题目链接 题意 : 就是把n个数安排在环上,要求每两个相邻的数之和一定是素数,第一个数一定是1.输出所有可能的排列. 思路 : 先打个素数表.然后循环去搜..... #include <cstdio> #include <cstring> #include <iostream> using namespace std ; ]; ] ,cs[]; int n ; void get_prime() { memset(prime,,sizeof(prime)); prime[…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 31031    Accepted Submission(s): 13755 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 20105    Accepted Submission(s): 9001 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

题目的意思就是在1到n的所有序列之间,找出所有相邻的数相加是素数的序列.Ps:题目是环,所以头和尾也要算哦~ 典型的dfs,然后剪枝. 这题目有意思的就是用java跑回在tle的边缘,第一次提交就tle了(服务器负载的问题吧),一模一样的第二次提交就ac了,侧面也反应了递归对stack的开销影响效率也是严重的.好了,上代码!! 题目传送门: HDU_1016 import java.util.Scanner; public class Main { public static final int…

一切见凝视. #include <cstdio> #include <iostream> #include <cstring> #include <algorithm> using namespace std; bool vis[22]; int n; int ans[22]; int top; bool isprime(int x)//推断素数 { for(int i=2;i<x;i++) if(x%i==0)return false; return…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 67252    Accepted Submission(s): 28829 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 34799    Accepted Submission(s): 15411 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1016 Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Problem Description A ring is compose of n circles as shown in diagram. Put natural number 1, 2…

传送门: http://acm.hdu.edu.cn/showproblem.php?pid=1016 Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 63806    Accepted Submission(s): 27457 Problem Description A ring is compos…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1016 题目大意:输入一个n,环从一开始到n,相邻两个数相加为素数. #include <iostream> #include <cstdio> #include <cstring> using namespace std; ],q[],n; int sushu(int n) { int i; ; i*i<=n; i++) ) ; ; } void dfs(int x,…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1016 哈哈,状态来了就是不一样,很快就A了. 注意的位置是,最后一个点,要与第一个点比较. #include <stdio.h> #include <string.h> ]= {}; ///是素数就是0 ]; ]; int n; void dfs(int k) { //printf("%d\n",k); ) { ; i<n; i++) printf("…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 18313    Accepted Submission(s): 8197 Problem Description A ring is compose of n circles as shown in diagram. Put natural numbe…

在刚刚写完代码的时候才发现我以前交过这道题,可是没有过. 后来因为不理解代码,于是也就不了了之了. 可说呢,那时的我哪知道什么DFS深搜的东西啊,而且对递归的理解也很肤浅. 这道题应该算HDU 2610 Sequence one的简化版,判重也非常简单. 其他也没有什么好说的了,直接上代码吧. //#define LOCAL #include <iostream> #include <cstdio> #include <cstring> #include <cma…

变形课 Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/65536 K (Java/Others)Total Submission(s): 19133    Accepted Submission(s): 6892 Problem Description 呃......变形课上Harry碰到了一点小麻烦,因为他并不像Hermione那样能够记住所有的咒语而随意的将一个棒球变成刺猬什么的,但是他发现了变形咒语的一个统一规…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 34846    Accepted Submission(s): 15441 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

Problem Description A ring is compose of n circles as shown in diagram. Put natural number 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 should always be 1…

题意是说对一个长度为 n 的数环进行排列,使得相邻两数的和为素数,按从小到大的顺序依次输出. 因为是环,所以总能调整成以 1 为序列首输出.用深度优先搜索的方法即可.在判断素数时由于 n 小于 20,所以两数的和小于 40,则只要手写小于 40 的素数数组即可. 代码如下: #include <bits/stdc++.h> using namespace std; ]; ]; ] = {,,,,,,,,,,,}; bool isprime(int m) { ; ; i < ; i++)…

A ring is compose of n circles as shown in diagram. Put natural number 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 should always be 1.   Inputn (0 < n <…

Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 25156    Accepted Submission(s): 11234 Problem Description A ring is compose of n circles as shown in diagram. Put natural num…

Problem Description There are N vertices connected by N−1 edges, each edge has its own length.The set { 1,2,3,…,N } contains a total of N! unique permutations, let’s say the i-th permutation is Pi and Pi,j is its j-th number.For the i-th permutation,…

Prime Ring Problem A ring is compose of n circles as shown in diagram. Put natural number 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 should always be 1.…

题意:一个规则的实心十二面体,它的 20个顶点标出世界著名的20个城市,你从一个城市出发经过每个城市刚好一次后回到出发的城市. 前20行的第i行有3个数,表示与第i个城市相邻的3个城市.第20行以后每行有1个数m,m<=20,m>=1.m=0退出 输出从第m个城市出发经过每个城市1次又回到m的所有路线,如有多条路线,按字典序输出,每行1条路线.每行首先输出是第几条路线.然后个一个: 后列出经过的城市 dfsdfsdfsdfsdfsdfs………… #include <iostream>…

题目大意: 给定1-n这n个数,组成以1开头的素数环,保证相邻两个数相加均为素数 题目用dfs搜索再回溯,这样碰到不成立的立刻退出递归,就减少了很多步骤,不然暴力来就是n!次复杂度,肯定是超时的 每次添入数据都要判断是否相邻数相加为素数,所以我们可以提前打个素数表,这样使自己判断素数更加方便 #include <cstdio> #include <cstring> using namespace std; #define N 22 ]; void prime_table() { m…