https://blog.csdn.net/libin56842/article/details/15028427
#include<bits/stdc++.h>
using namespace std;
int mp[25][5];
bool VIS[25];
int ans[25];
int T = 1;
int n, m;
void DFS(int u, int cnt)
{
VIS[u] = 1;
ans[cnt] = u;
for (int i = 0; i<3; i++)
{
int v = mp[u][i];
if (v == m && cnt == 19)
{
printf("%d: ", T++);
for (int j = 0; j < 20; j++)
cout << ans[j] << " ";
cout << m << endl;
}
if (!VIS[v]) DFS(v, cnt + 1);
}
VIS[u] = 0;
}
int main()
{
for (int i = 1; i <= 20; i++)
{
cin >> mp[i][0] >> mp[i][1] >> mp[i][2];
sort(mp[i], mp[i] + 3);
//如有多条路线,按字典序输出
}
while (cin>>m&&m)
{
memset(VIS, 0, sizeof(VIS));
DFS(m, 0);
}
return 0;
}