简单DFS
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#include <cstdio>bool
used[21];bool
prim[41];int now[21];int i,j,n;void
out(){ printf("1"); for(int
i=2;i<=n;i++) printf(" %d",now[i]); printf("\n");}void
dfs(int
step){ if
(step==n&&prim[now[n]+1]) out();//注意是==，=导致WA for(int
i=2;i<=n;i++) if
((!used[i])&&(prim[i+now[step]])) { used[i]=true; now[step+1]=i; dfs(step+1); used[i]=false; } }int
main(){ int
cnt=1; for
(int i=2;i<21;i++)used[i]=false; for
(int i=1;i<41;i++)prim[i]=true; for(int
i=2;i<41;i++) { if(!prim[i]) continue; for(int
j=2*i; j<41; j+=i)prim[j]=false; } now[1]=1; used[1]=true; while(scanf("%d",&n)!=EOF) { printf("Case %d:\n",cnt++); dfs(1); puts(""); }} |
原文：http://www.cnblogs.com/forever97/p/3542418.html