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 #include <iostream>
2
3 using namespace std;
4
5 int Map[21][21] = { 0 }; //邻接矩阵
6 int path[21]; //记录每一次答案的路线
7 bool visited[21] = { false };
8 int num = 1; //路径的编号
9
10
11 void dfs(int city, int cur) //city为当前访问的城市，已经访问了cur个城市
12 {
13 path[cur] = city; //将当前城市记录在路径上
14 visited[city] = true;
15
16 if (cur == 20) //如果已经访问了20个城市
17 {
18 if (Map[city][path[1]] == 1) //这个城市与起点城市之间存在路径
19 {
20 cout << num << ": ";
21 num++;
22 for (int i = 1; i <= 20; ++i)
23 cout << path[i] << ' ';
24 cout << path[1] << endl;
25 }
26 }
27
28 for (int i = 1; i <= 20; ++i)
29 {
30 if (Map[i][city] == 1 && !visited[i])
31 {
32 dfs(i, cur+1); //注意此处不能是++cur
33 visited[i] = false; //dfs完要把访问过的顶点重新置为未访问状态
34 }
35 }
36
37 }
38
39
40 int main()
41 {
42 //创建邻接矩阵
43 int city;
44 for (int i = 1; i <= 20; ++i)
45 {
46 for (int j = 1; j <= 3; ++j)
47 {
48 cin >> city;
49 Map[i][city] = 1;
50 }
51 }
52
53 int m;
54 while (cin >> m && m != 0)
55 {
56 dfs(m, 1);
57 num = 1;
58 }
59
60
61 return 0;
62
63 }
