HDU-2181-哈密顿绕行世界问题 [dfs]

题目传送门

#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
bool book[30];
int mp[30][3];
int ans[30];
int cas;
void dfs(int x, int stp, int m)
{
    book[x] = false;
    ans[stp] = x;
    for (int i = 0; i < 3; i++)
    {
        if (mp[x][i]==m && stp==20)
        {
            printf("%d:  ", ++cas);
            for (int i = 1; i <= 20; i++)
            {
                printf("%d ", ans[i]);
            }
            printf("%d\n", m);
        }
        if (book[mp[x][i]])
        {
            dfs(mp[x][i], stp+1, m);
        }
    }
    book[x] = true;
    return;
}
int main(void)
{
    for (int i = 1; i <= 20; i++)
        scanf("%d %d %d", &mp[i][0], &mp[i][1], &mp[i][2]);
    int m;
    while (scanf("%d", &m), m)
    {
        cas = 0;
        memset(book, true, sizeof(book));
        dfs(m, 1, m);
    }
    return 0;
}