哈密顿绕行世界问题

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。 

Input

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. 

Output

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.参看Sample output 

Sample Input

2 5 201 3 122 4 103 5 81 4 65 7 196 8 174 7 98 10 163 9 1110 12 152 11 1312 14 2013 15 1811 14 169 15 177 16 1814 17 196 18 201 13 1950

Sample Output

1:  5 1 2 3 4 8 7 17 18 14 15 16 9 10 11 12 13 20 19 6 52:  5 1 2 3 4 8 9 10 11 12 13 20 19 18 14 15 16 17 7 6 53:  5 1 2 3 10 9 16 17 18 14 15 11 12 13 20 19 6 7 8 4 54:  5 1 2 3 10 11 12 13 20 19 6 7 17 18 14 15 16 9 8 4 55:  5 1 2 12 11 10 3 4 8 9 16 15 14 13 20 19 18 17 7 6 56:  5 1 2 12 11 15 14 13 20 19 18 17 16 9 10 3 4 8 7 6 57:  5 1 2 12 11 15 16 9 10 3 4 8 7 17 18 14 13 20 19 6 58:  5 1 2 12 11 15 16 17 18 14 13 20 19 6 7 8 9 10 3 4 59:  5 1 2 12 13 20 19 6 7 8 9 16 17 18 14 15 11 10 3 4 510:  5 1 2 12 13 20 19 18 14 15 11 10 3 4 8 9 16 17 7 6 511:  5 1 20 13 12 2 3 4 8 7 17 16 9 10 11 15 14 18 19 6 512:  5 1 20 13 12 2 3 10 11 15 14 18 19 6 7 17 16 9 8 4 513:  5 1 20 13 14 15 11 12 2 3 10 9 16 17 18 19 6 7 8 4 514:  5 1 20 13 14 15 16 9 10 11 12 2 3 4 8 7 17 18 19 6 515:  5 1 20 13 14 15 16 17 18 19 6 7 8 9 10 11 12 2 3 4 516:  5 1 20 13 14 18 19 6 7 17 16 15 11 12 2 3 10 9 8 4 517:  5 1 20 19 6 7 8 9 10 11 15 16 17 18 14 13 12 2 3 4 518:  5 1 20 19 6 7 17 18 14 13 12 2 3 10 11 15 16 9 8 4 519:  5 1 20 19 18 14 13 12 2 3 4 8 9 10 11 15 16 17 7 6 520:  5 1 20 19 18 17 16 9 10 11 15 14 13 12 2 3 4 8 7 6 521:  5 4 3 2 1 20 13 12 11 10 9 8 7 17 16 15 14 18 19 6 522:  5 4 3 2 1 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 523:  5 4 3 2 12 11 10 9 8 7 6 19 18 17 16 15 14 13 20 1 524:  5 4 3 2 12 13 14 18 17 16 15 11 10 9 8 7 6 19 20 1 525:  5 4 3 10 9 8 7 6 19 20 13 14 18 17 16 15 11 12 2 1 526:  5 4 3 10 9 8 7 17 16 15 11 12 2 1 20 13 14 18 19 6 527:  5 4 3 10 11 12 2 1 20 13 14 15 16 9 8 7 17 18 19 6 528:  5 4 3 10 11 15 14 13 12 2 1 20 19 18 17 16 9 8 7 6 529:  5 4 3 10 11 15 14 18 17 16 9 8 7 6 19 20 13 12 2 1 530:  5 4 3 10 11 15 16 9 8 7 17 18 14 13 12 2 1 20 19 6 531:  5 4 8 7 6 19 18 17 16 9 10 3 2 12 11 15 14 13 20 1 532:  5 4 8 7 6 19 20 13 12 11 15 14 18 17 16 9 10 3 2 1 533:  5 4 8 7 17 16 9 10 3 2 1 20 13 12 11 15 14 18 19 6 534:  5 4 8 7 17 18 14 13 12 11 15 16 9 10 3 2 1 20 19 6 535:  5 4 8 9 10 3 2 1 20 19 18 14 13 12 11 15 16 17 7 6 536:  5 4 8 9 10 3 2 12 11 15 16 17 7 6 19 18 14 13 20 1 537:  5 4 8 9 16 15 11 10 3 2 12 13 14 18 17 7 6 19 20 1 538:  5 4 8 9 16 15 14 13 12 11 10 3 2 1 20 19 18 17 7 6 539:  5 4 8 9 16 15 14 18 17 7 6 19 20 13 12 11 10 3 2 1 540:  5 4 8 9 16 17 7 6 19 18 14 15 11 10 3 2 12 13 20 1 541:  5 6 7 8 4 3 2 12 13 14 15 11 10 9 16 17 18 19 20 1 542:  5 6 7 8 4 3 10 9 16 17 18 19 20 13 14 15 11 12 2 1 543:  5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1 2 3 4 544:  5 6 7 8 9 16 17 18 19 20 1 2 12 13 14 15 11 10 3 4 545:  5 6 7 17 16 9 8 4 3 10 11 15 14 18 19 20 13 12 2 1 546:  5 6 7 17 16 15 11 10 9 8 4 3 2 12 13 14 18 19 20 1 547:  5 6 7 17 16 15 11 12 13 14 18 19 20 1 2 3 10 9 8 4 548:  5 6 7 17 16 15 14 18 19 20 13 12 11 10 9 8 4 3 2 1 549:  5 6 7 17 18 19 20 1 2 3 10 11 12 13 14 15 16 9 8 4 550:  5 6 7 17 18 19 20 13 14 15 16 9 8 4 3 10 11 12 2 1 551:  5 6 19 18 14 13 20 1 2 12 11 15 16 17 7 8 9 10 3 4 552:  5 6 19 18 14 15 11 10 9 16 17 7 8 4 3 2 12 13 20 1 553:  5 6 19 18 14 15 11 12 13 20 1 2 3 10 9 16 17 7 8 4 554:  5 6 19 18 14 15 16 17 7 8 9 10 11 12 13 20 1 2 3 4 555:  5 6 19 18 17 7 8 4 3 2 12 11 10 9 16 15 14 13 20 1 556:  5 6 19 18 17 7 8 9 16 15 14 13 20 1 2 12 11 10 3 4 557:  5 6 19 20 1 2 3 10 9 16 15 11 12 13 14 18 17 7 8 4 558:  5 6 19 20 1 2 12 13 14 18 17 7 8 9 16 15 11 10 3 4 559:  5 6 19 20 13 12 11 10 9 16 15 14 18 17 7 8 4 3 2 1 560:  5 6 19 20 13 14 18 17 7 8 4 3 10 9 16 15 11 12 2 1 5

简单的DFS因为20^3所以放心的让他跑吧。

#include <bits/stdc++.h>using namespace std;const int INF = 0x3f3f3f3f;const int maxn = 30;int Map[maxn][maxn],u,v,w,n;int vist[maxn],Step[maxn];int flag = 0;int cnt;bool judge(){    for(int i = 1; i <= 20; i++)        if(vist[i] == 0)            return false;    return true;}void DFS(int x,int step){    Step[step] = x;    if(judge() && x == n){        printf("%d:  ",++cnt);        for(int i = 0; i < 20; i++)            printf("%d ",Step[i]);        printf("%d\n",Step[20]);    }    for(int i = 1; i <= 20; i++){        if(!vist[i] && Map[x][i]){            vist[i] = 1;            DFS(i,step+1);            vist[i] = 0;        }    }}int main(){    memset(Map,0,sizeof(Map));    for(int i = 1; i <= 20; i++){        scanf("%d %d %d",&u,&v,&w);        Map[i][u] = Map[u][i] = 1;        Map[i][v] = Map[v][i] = 1;        Map[i][w] = Map[w][i] = 1;    }    while(~scanf("%d",&n) && n){        cnt = 0;        memset(vist,0,sizeof(vist));        DFS(n,0);    }    return 0;}