用最笨的搜索與回溯

（大寫的N的值對應方格的邊長，下面的代碼N=5即是5*5的方格）

#include <fstream>

  N =  , n = N +   , m = n +  way[] = {  wpp( ++ ( way[ lev ] == = +  path(  grid[][] ,  i ,  j ,  ( dir ==  ) ++  ( dir ==  ) ++  ( dir ==  ) -- -- ( grid[i][j] )  ( i == n && j === =  i =  , j =  grid[][] = { (  a =  ; a != m ; ++][a] = -][a] = ] = -] = =  bit =  ( ; ! way[ bit ] ; -- , way[ bit-- ( bit !=  ) printf(  , way[ bit--