text: #include <iostream>
  #include <sstream>
  #include <iterator>
  #include <vector>
  
  //------------------------------------------------------------------------------
  using namespace std;
  
  //------------------------------------------------------------------------------
  struct node
  {
      int val;
      unsigned char neighbors;
  };
  //------------------------------------------------------------------------------
  class hSolver
  {
  public:
      hSolver()
      {
  	dx[0] = -1; dx[1] = 0; dx[2] = 1; dx[3] = -1; dx[4] = 1; dx[5] = -1; dx[6] = 0; dx[7] = 1;
  	dy[0] = -1; dy[1] = -1; dy[2] = -1; dy[3] = 0; dy[4] = 0; dy[5] = 1; dy[6] = 1; dy[7] = 1;
      }
  
      void solve( vector<string>& puzz, int max_wid )
      {
  	if( puzz.size() < 1 ) return;
  	wid = max_wid; hei = static_cast<int>( puzz.size() ) / wid;
  	int len = wid * hei, c = 0; max = 0;
  	arr = new node[len]; memset( arr, 0, len * sizeof( node ) );
  	weHave = new bool[len + 1]; memset( weHave, 0, len + 1 );
  		
  	for( vector<string>::iterator i = puzz.begin(); i != puzz.end(); i++ )
  	{
  	    if( ( *i ) == "*" ) {    arr[c++].val = -1; continue; }
  	    arr[c].val = atoi( ( *i ).c_str() );
  	    if( arr[c].val > 0 ) weHave[arr[c].val] = true;
  	    if( max < arr[c].val ) max = arr[c].val;
  	    c++;
  	}
  
  	solveIt(); c = 0;
  	for( vector<string>::iterator i = puzz.begin(); i != puzz.end(); i++ )
  	{
  	    if( ( *i ) == "." )
  	    {
  		ostringstream o; o << arr[c].val;
  		( *i ) = o.str();
  	    }
  	    c++;
  	}
  	delete [] arr;
  	delete [] weHave;
      }
  
  private:
      bool search( int x, int y, int w )
      {
  	if( w == max ) return true;
  
  	node* n = &arr[x + y * wid];
  	n->neighbors = getNeighbors( x, y );
  	if( weHave[w] )
  	{
  	    for( int d = 0; d < 8; d++ )
  	    {
  		if( n->neighbors & ( 1 << d ) )
  		{
  		    int a = x + dx[d], b = y + dy[d];
  		    if( arr[a + b * wid].val == w )
  		    if( search( a, b, w + 1 ) ) return true;
  		}
  	    }
  	    return false;
  	}
  
  	for( int d = 0; d < 8; d++ )
  	{
  	    if( n->neighbors & ( 1 << d ) )
  	    {
  		int a = x + dx[d], b = y + dy[d];
  		if( arr[a + b * wid].val == 0 )
  		{
  		    arr[a + b * wid].val = w;
  		    if( search( a, b, w + 1 ) ) return true;
  		    arr[a + b * wid].val = 0;
  		}
  	    }
  	}
  	return false;
      }
  
      unsigned char getNeighbors( int x, int y )
      {
  	unsigned char c = 0; int m = -1, a, b;
  	for( int yy = -1; yy < 2; yy++ )
  	    for( int xx = -1; xx < 2; xx++ )
  	    {
  		if( !yy && !xx ) continue;
  		m++; a = x + xx, b = y + yy;
  		if( a < 0 || b < 0 || a >= wid || b >= hei ) continue;
  		if( arr[a + b * wid].val > -1 ) c |= ( 1 << m );
  	    }
  	return c;
      }
  
      void solveIt()
      {
  	int x, y; findStart( x, y );
  	if( x < 0 ) { cout << "\nCan't find start point!\n"; return; }
  	search( x, y, 2 );
      }
  
      void findStart( int& x, int& y )
      {
  	for( int b = 0; b < hei; b++ )
  	    for( int a = 0; a < wid; a++ )
  		if( arr[a + wid * b].val == 1 ) { x = a; y = b; return; }
  	x = y = -1;
      }
  
      int wid, hei, max, dx[8], dy[8];
      node* arr;
      bool* weHave;
  };
  //------------------------------------------------------------------------------
  int main( int argc, char* argv[] )
  {
      int wid;
      string p = ". 33 35 . . * * * . . 24 22 . * * * . . . 21 . . * * . 26 . 13 40 11 * * 27 . . . 9 . 1 * * * . . 18 . . * * * * * . 7 . . * * * * * * 5 ."; wid = 8;
      //string p = "54 . 60 59 . 67 . 69 . . 55 . . 63 65 . 72 71 51 50 56 62 . * * * * . . . 14 * * 17 . * 48 10 11 * 15 . 18 . 22 . 46 . * 3 . 19 23 . . 44 . 5 . 1 33 32 . . 43 7 . 36 . 27 . 31 42 . . 38 . 35 28 . 30"; wid = 9;
      //string p = ". 58 . 60 . . 63 66 . 57 55 59 53 49 . 65 . 68 . 8 . . 50 . 46 45 . 10 6 . * * * . 43 70 . 11 12 * * * 72 71 . . 14 . * * * 30 39 . 15 3 17 . 28 29 . . 40 . . 19 22 . . 37 36 . 1 20 . 24 . 26 . 34 33"; wid = 9;
  
      istringstream iss( p ); vector<string> puzz;
      copy( istream_iterator<string>( iss ), istream_iterator<string>(), back_inserter<vector<string> >( puzz ) );
      hSolver s; s.solve( puzz, wid );
  
      int c = 0;
      for( vector<string>::iterator i = puzz.begin(); i != puzz.end(); i++ )
      {
  	if( ( *i ) != "*" && ( *i ) != "." )
  	{
  	    if( atoi( ( *i ).c_str() ) < 10 ) cout << "0";
  	    cout << ( *i ) << " ";
  	}
  	else cout << "   ";
  	if( ++c >= wid ) { cout << endl; c = 0; }
      }
      cout << endl << endl;
      return system( "pause" );
  }
  //--------------------------------------------------------------------------------------------------
  