title: how could I solve 0HH1 with backtracking in c++
body: <p>I'm trying to solve this puzzle using backtrack algorithm. In c++ 
  I face the problem that I couldn't apply the backtrack</p>
  
  <pre><code>void try1(int x,int y)
  {  
      int k=-1;
      do{
          k++ ;
          if(check_color(c[k],x,y))
          {
              h[x][y]=c[k];// c[k]= r or b;          
             if ( check_full() &amp;&amp; check_array() &amp;&amp; check_equal() )
             {
                 cout&lt;&lt;"coloring had finished"; cout&lt;&lt;"  \n  ";
                 print(h); getch();
             }         
             else 
             {
                 if(y==9&amp;&amp;x&lt;9)
                 {
                     y = -1; x++;
                 }
                 while(y&lt;9 )
                 {
                      y=y+1;
                      if(h[x][y]==' ')
                          try1(x,y);
                       /* here should be the backtrack I think
                         if(q=='n')
                        { x--;cout&lt;&lt;h[x][y];
                          if(h[x][y]=='b'){h[x][y]='r';}
                          else {h[x][y]='b';}}*/                 
                      else if ( y==9 &amp;&amp; x&lt;9 ){
                          y=-1 ;x++ ; 
                      }
                  }
              }
          }
      } while ( k&lt;1 )  ; 
  }
  </code></pre>
  
  <p>could anyone help me???
  Ineed all possible solution back tracking</p>