Prime Ring Problem Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 34609    Accepted Submission(s): 15327 Problem Description A ring is compose of n circles as shown in diagram. Put natural numb…

UVA - 524 Prime Ring Problem Time Limit:3000MS     Memory Limit:0KB     64bit IO Format:%lld & %llu Description A ring is composed of n (even number) circles as shown in diagram. Put natural numbers  into each circle separately, and the sum of number…

题意  把1到n这n个数以1为首位围成一圈  输出全部满足随意相邻两数之和均为素数的全部排列 直接枚举排列看是否符合肯定会超时的  n最大为16  利用回溯法 边生成边推断  就要快非常多了 #include<cstdio> using namespace std; const int N = 50; int p[N], vis[N], a[N], n; int isPrime(int k) { for(int i = 2; i * i <= k; ++i) if(k % i == 0)…

 Prime Ring Problem Time Limit: 10 Seconds      Memory Limit: 32768 KB 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…

  Prime Ring Problem                                                                       时间限制: 2000ms               内存限制: 32768KB                HDU       ID: 1016 题目描述 A ring is compose of n circles as shown in diagram. Put natural number 1, 2, ..…

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…

http://acm.hdu.edu.cn/showproblem.php?pid=1016 题意:输入n,代表有一个包含n个节点的环,在环中的节点中填入1,2...n-1,n,要求填入的数与左边的数之和,与右边的数之和,都为素数 输出所有符合要求的环(第一个数总为1) 用DFS模拟,从第2位到第n位依次选取一个与上一个选取的数之和为素数的数 直到选取完第n个数,判断第n个数和1之和是否为素数,是则输出,否则不进行操作,判断完毕返回上一层 直到遍历完所有情况 *:因为素数必然是奇数,所以一条符合…

http://acm.hdu.edu.cn/showproblem.php?pid=1258 关键点就是一次递归里面一样的数字只能选一次. #include <cstdio> #include <cstring> int n,t; ],c[]; bool flag; void dfs(int k,int sum,int l) { if(sum==t) { ;i<l-;i++) printf("%d+",c[i]); printf(]); flag=; re…

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): 40339    Accepted Submission(s): 17813 Problem Description A ring is compose of n circles as shown in diagram. Put natural num…