Hdoj 1016 Prime Ring problem

Problem Descriptiona 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 the adjacent circles should is a PR Ime.

Note:the number of first circle should always be 1.

INPUTN (0 < n < 20).

Outputthe output format is shown as sample below. Each row represents a series of circle numbers in the ring beginning from 1 clockwisely and anticlockwisely. The order of numbers must satisfy the above requirements. Print Solutions in lexicographical order.

You is to write a program, that completes above process.

Print a blank line after each case.

Sample INPUT6 8

Sample outputcase 1:1 4 3 2 5 6 1 6 5 2 3 4Case 2:1 2 3 8 5 6 7 4 1 2 5 8 3 4 7 6 1 4 7 6 5 8 3 2 1 6 7 4 3 8 5 2

1#include <stdio.h>2#include <string.h>3 intN;4 intvis[ -], a[ -];5 intJudgeints)6 {7     intFlag =1;8      for(inti =2; I <= s/2; i++)9     {Ten         if(s%i = =0) One         { AFlag =0; -              Break; -         } the     } -     returnFlag; - }  - voidDfsintSintCNT) + { -     intI, J; +     if(CNT = = n+1&& Judge (a[1]+A[n])) A     { at          for(j =1; J < n+1; J + +) -         { -             if(J! =1) -printf" "); -printf"%d", A[j]); -         } inprintf"\ n"); -         return ; to     } +      for(i =1; I <= N; i++) -     { the         if(Judge (i + s) &&!Vis[i]) *         { $A[CNT] =i;Panax NotoginsengVis[i] =1; -DFS (i, CNT +1); theVis[i] =0; +              A         } the     } +     return ; - } $ intMain () $ { -     intnum =1; -      while(~SCANF ("%d", &N)) the     { -printf"Case %d:\n", num++);Wuyimemset (Vis,0,sizeof(Vis)); thevis[1] =1; -a[1] =1; WuDfs1,2); -printf"\ n"); About     } $     return 0; -}

Hdoj 1016 Prime Ring problem