（深度搜索）The House Of Santa Claus

 

In your childhood you most likely had to solve the riddle of the house of Santa Claus. Do you remember that the importance was on drawing the house in a stretch without lifting the pencil and not drawing a line twice? As a reminder it has to look like shown in Figure 1.

 
Figure: The House of Santa Claus

Well, a couple of years later, like now, you have to ``draw'' the house again but on the computer. As one possibility is not enough, we require all the possibilities when starting in the lower left corner. Follow the example in Figure 2 while defining your stretch.

 
Figure: This Sequence would give the Outputline 153125432

All the possibilities have to be listed in the outputfile by increasing order, meaning that 1234... is listed before 1235... .

Output

So, an outputfile could look like this:

12435123
13245123
...
15123421

 

使用递归进行搜索：

#include<iostream>
#include <string >
#include <cstring >
using namespace std;
int map[6][6];                 //在这里注意第一行时没有用的，全部设置为0
void makemap()
{
 memset(map,0,sizeof(map));
 for(int i=1;i<=5;i++)
  for(int j=1;j<=5;j++)
   if(i!=j)           //标记除了自己外不能访问自己
    map[i][j]=1;
 map[4][1]=map[1][4]=0;      //由于2和4  1和4不能直接相连，所以为0
 map[4][2]=map[2][4]=0;
}
void dfs(int x,int k,string s)
{
 s=s+char(x+'0');    //记录路径
 if(k==8)            //记录路径的长度
 {
  cout<<s<<endl;
  return ;
 }
 for(int y=1;y<=5;y++)
  if(map[x][y])
  {
   map[x][y]=map[y][x]=0;
   dfs(y,k+1,s);              //递归求出所有路线
   map[x][y]=map[y][x]=1;//恢复原形状
  }
}
int main ()
{
 makemap();
 dfs(1,0,""); //第三个参数为路径字符串
  return 0;
}