HDU 2181 哈密顿绕行世界问题 (DFS)

哈密顿绕行世界问题

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1509    Accepted Submission(s): 959

Problem Description

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 20 1 3 12 2 4 10 3 5 8 1 4 6 5 7 19 6 8 17 4 7 9 8 10 16 3 9 11 10 12 15 2 11 13 12 14 20 13 15 18 11 14 16 9 15 17 7 16 18 14 17 19 6 18 20 1 13 19 5 0

 

Sample Output

1: 5 1 2 3 4 8 7 17 18 14 15 16 9 10 11 12 13 20 19 6 5 2: 5 1 2 3 4 8 9 10 11 12 13 20 19 18 14 15 16 17 7 6 5 3: 5 1 2 3 10 9 16 17 18 14 15 11 12 13 20 19 6 7 8 4 5 4: 5 1 2 3 10 11 12 13 20 19 6 7 17 18 14 15 16 9 8 4 5 5: 5 1 2 12 11 10 3 4 8 9 16 15 14 13 20 19 18 17 7 6 5 6: 5 1 2 12 11 15 14 13 20 19 18 17 16 9 10 3 4 8 7 6 5 7: 5 1 2 12 11 15 16 9 10 3 4 8 7 17 18 14 13 20 19 6 5 8: 5 1 2 12 11 15 16 17 18 14 13 20 19 6 7 8 9 10 3 4 5 9: 5 1 2 12 13 20 19 6 7 8 9 16 17 18 14 15 11 10 3 4 5 10: 5 1 2 12 13 20 19 18 14 15 11 10 3 4 8 9 16 17 7 6 5 11: 5 1 20 13 12 2 3 4 8 7 17 16 9 10 11 15 14 18 19 6 5 12: 5 1 20 13 12 2 3 10 11 15 14 18 19 6 7 17 16 9 8 4 5 13: 5 1 20 13 14 15 11 12 2 3 10 9 16 17 18 19 6 7 8 4 5 14: 5 1 20 13 14 15 16 9 10 11 12 2 3 4 8 7 17 18 19 6 5 15: 5 1 20 13 14 15 16 17 18 19 6 7 8 9 10 11 12 2 3 4 5 16: 5 1 20 13 14 18 19 6 7 17 16 15 11 12 2 3 10 9 8 4 5 17: 5 1 20 19 6 7 8 9 10 11 15 16 17 18 14 13 12 2 3 4 5 18: 5 1 20 19 6 7 17 18 14 13 12 2 3 10 11 15 16 9 8 4 5 19: 5 1 20 19 18 14 13 12 2 3 4 8 9 10 11 15 16 17 7 6 5 20: 5 1 20 19 18 17 16 9 10 11 15 14 13 12 2 3 4 8 7 6 5 21: 5 4 3 2 1 20 13 12 11 10 9 8 7 17 16 15 14 18 19 6 5 22: 5 4 3 2 1 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 23: 5 4 3 2 12 11 10 9 8 7 6 19 18 17 16 15 14 13 20 1 5 24: 5 4 3 2 12 13 14 18 17 16 15 11 10 9 8 7 6 19 20 1 5 25: 5 4 3 10 9 8 7 6 19 20 13 14 18 17 16 15 11 12 2 1 5 26: 5 4 3 10 9 8 7 17 16 15 11 12 2 1 20 13 14 18 19 6 5 27: 5 4 3 10 11 12 2 1 20 13 14 15 16 9 8 7 17 18 19 6 5 28: 5 4 3 10 11 15 14 13 12 2 1 20 19 18 17 16 9 8 7 6 5 29: 5 4 3 10 11 15 14 18 17 16 9 8 7 6 19 20 13 12 2 1 5 30: 5 4 3 10 11 15 16 9 8 7 17 18 14 13 12 2 1 20 19 6 5 31: 5 4 8 7 6 19 18 17 16 9 10 3 2 12 11 15 14 13 20 1 5 32: 5 4 8 7 6 19 20 13 12 11 15 14 18 17 16 9 10 3 2 1 5 33: 5 4 8 7 17 16 9 10 3 2 1 20 13 12 11 15 14 18 19 6 5 34: 5 4 8 7 17 18 14 13 12 11 15 16 9 10 3 2 1 20 19 6 5 35: 5 4 8 9 10 3 2 1 20 19 18 14 13 12 11 15 16 17 7 6 5 36: 5 4 8 9 10 3 2 12 11 15 16 17 7 6 19 18 14 13 20 1 5 37: 5 4 8 9 16 15 11 10 3 2 12 13 14 18 17 7 6 19 20 1 5 38: 5 4 8 9 16 15 14 13 12 11 10 3 2 1 20 19 18 17 7 6 5 39: 5 4 8 9 16 15 14 18 17 7 6 19 20 13 12 11 10 3 2 1 5 40: 5 4 8 9 16 17 7 6 19 18 14 15 11 10 3 2 12 13 20 1 5 41: 5 6 7 8 4 3 2 12 13 14 15 11 10 9 16 17 18 19 20 1 5 42: 5 6 7 8 4 3 10 9 16 17 18 19 20 13 14 15 11 12 2 1 5 43: 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 1 2 3 4 5 44: 5 6 7 8 9 16 17 18 19 20 1 2 12 13 14 15 11 10 3 4 5 45: 5 6 7 17 16 9 8 4 3 10 11 15 14 18 19 20 13 12 2 1 5 46: 5 6 7 17 16 15 11 10 9 8 4 3 2 12 13 14 18 19 20 1 5 47: 5 6 7 17 16 15 11 12 13 14 18 19 20 1 2 3 10 9 8 4 5 48: 5 6 7 17 16 15 14 18 19 20 13 12 11 10 9 8 4 3 2 1 5 49: 5 6 7 17 18 19 20 1 2 3 10 11 12 13 14 15 16 9 8 4 5 50: 5 6 7 17 18 19 20 13 14 15 16 9 8 4 3 10 11 12 2 1 5 51: 5 6 19 18 14 13 20 1 2 12 11 15 16 17 7 8 9 10 3 4 5 52: 5 6 19 18 14 15 11 10 9 16 17 7 8 4 3 2 12 13 20 1 5 53: 5 6 19 18 14 15 11 12 13 20 1 2 3 10 9 16 17 7 8 4 5 54: 5 6 19 18 14 15 16 17 7 8 9 10 11 12 13 20 1 2 3 4 5 55: 5 6 19 18 17 7 8 4 3 2 12 11 10 9 16 15 14 13 20 1 5 56: 5 6 19 18 17 7 8 9 16 15 14 13 20 1 2 12 11 10 3 4 5 57: 5 6 19 20 1 2 3 10 9 16 15 11 12 13 14 18 17 7 8 4 5 58: 5 6 19 20 1 2 12 13 14 18 17 7 8 9 16 15 11 10 3 4 5 59: 5 6 19 20 13 12 11 10 9 16 15 14 18 17 7 8 4 3 2 1 5 60: 5 6 19 20 13 14 18 17 7 8 4 3 10 9 16 15 11 12 2 1 5

 

 

 

DFS，刚开始的时候以为是图，潜移默化的觉得不会做，想了半天才弄出来，注意判重。

#include <iostream>

#include <cstring>

#include <cstdio>

#include <string>

using    namespace    std;



int    MAP[25][25];

int    VIS[25];

int    ANS[25];

int    M,COUNT;



void    dfs(int i,int k);

int    main(void)

{

    int    a,b,c;

    int    m;



    memset(MAP,0,sizeof(MAP));

    for(int i = 1;i <= 20;i ++)

    {

        scanf("%d%d%d",&a,&b,&c);

        MAP[i][a] = MAP[a][i] = 1;

        MAP[i][b] = MAP[b][i] = 1;

        MAP[i][c] = MAP[c][i] = 1;

    }

    while(scanf("%d",&M) && M)

    {

        memset(VIS,0,sizeof(VIS));

        COUNT = 1;

        VIS[M] = 1;

        ANS[0] = M;

        dfs(M,1);

    }



    return    0;

} 



void    dfs(int num,int k)

{

    int    flag = 1;

    for(int i = 1;i <= 20;i ++)

        if(!VIS[i] && MAP[i][num])

        {

            flag = 0;

            ANS[k] = i;

            VIS[i] = 1;

            dfs(i,k + 1);

            VIS[i] = 0;

        }

    if(k == 20 && MAP[ANS[19]][M])

    {

        printf("%d:  ",COUNT);

        for(int i = 0;i < 20;i ++)

            printf("%d ",ANS[i]);

        printf("%d\n",M);

        COUNT ++;

    }

}