Y-wing就比较简单一点,如果存在三个格辅数分别为:D1(AB),D2(AC),D3(BC),且D1与D2在同一规则上,D1与D3在同一规则上,D2与D3不在同一规则上,则与D2和D3在同一规则上的D4中的辅数C可删减掉

 

图中绿色组成Y-wing,Y-wing删减后可删减掉紫色单元中的5,以后就能用单链来解了

对数字5,(4,3)(4,7)(9,7)(9,2)组成单链(链长为单数3)

程序如下:

<?
/*  AB  --- BC
 *  AC       C
 *
 */
/* 找所有对 */
function getdouble($arrdu)
{
 $ret = array();
 foreach($arrdu as $i => $v)
 {
  if(strlen($v)==3)
  {
   $ret[$v{1}][] = $i;
   $ret[$v{2}][] = $i;
  }
 }
 //print_r($ret);
 return $ret;
}
function y_wing(&$arrdu)
{
 //outit2($arrdu);
 GLOBAL $rule,$initstr,$r_row,$r_col,$r_box;
 $max = true;
 $ret = 0;
 
 while($max)
 {
  $max = false;
  $narr = str_split(substr($initstr,1)); //1,2,3,4,...
  $alldouble = getdouble($arrdu);
  
  foreach($narr as $num)
  {
   //echo "NUM $num\n";
   for($i=0;   $i<count($alldouble[$num]);$i++)
   for($j=$i+1;$j<count($alldouble[$num]);$j++)
   foreach($alldouble[$num] as $i)
   foreach($alldouble[$num] as $j)
   if( $j > $i
   && $r_row[$i] != $r_row[$j]  //找两个不同的单元格,都包含C(num)
   && $r_col[$i] != $r_col[$j]  //且要求这两个格不在同一行/列/盒
   && $r_box[$i] != $r_box[$j]  //为AC,BC样式
   && $arrdu[$i] != $arrdu[$j]
   )
   {
    //再找是否存在一个关键点 AB
    $first = true;
    $a = str_replace("$num",'',substr($arrdu[$i],1));
    $b = str_replace("$num",'',substr($arrdu[$j],1));
    //echo "$i $j $a $b\n";
    $q = array_intersect( $alldouble[$a],$alldouble[$b] );
    if(count($q)>0)
    foreach($q as $r)
    if(( $r_row[$i] == $r_row[$r] || $r_col[$i] == $r_col[$r] || $r_box[$i] == $r_box[$r])
    && ( $r_row[$j] == $r_row[$r] || $r_col[$j] == $r_col[$r] || $r_box[$j] == $r_box[$r])
    )
    {
     //找到了
     //echo "Fund\n";
     //outit2($arrdu);
     foreach($arrdu as $m => $n)
     if( $n{0} === '0'
     && strpos($n,"$num") !== false
     && $m != $i && $m != $j && $m != $r
     && ( $r_row[$i] == $r_row[$m] || $r_col[$i] == $r_col[$m] || $r_box[$i] == $r_box[$m])
     && ( $r_row[$j] == $r_row[$m] || $r_col[$j] == $r_col[$m] || $r_box[$j] == $r_box[$m])
     )
     {
      $new = str_replace("$num",'',$n);
      $arrdu[$m] = $new;
      if($GLOBALS['debug'])
      {
       if($first)
       {
        echo "Y-wing(A$a,B$b,C$num):AB:".bit2place($r)." AC:".bit2place($j)
            ." BC:".bit2place($i)."\n";
        $first = false;
       }
       echo "        ...".bit2place($m)." $n -> $new \n";
      }      
      $max = true;
      $ret = 1;
      if(onlyone($arrdu)==-1)return -1;
     }
    }
   }
  }
 }
 return $ret;
}

?>

 

运行结果:

D:\mywebhtdocs\do\game\dushu\ok>php do.php 3008027150079018030815379060000030090
03196408900700001000378602806000107702619084
Intersection 4 in Row7 remove from Box7
         ...(8,2)03459 -> 0359
Intersection 2 in Col7 remove from Box6
         ...(4,8)02567 -> 0567
         ...(5,8)0257 -> 057
         ...(6,8)02356 -> 0356
Intersection 4 in Box2 remove from Col5
         ...(4,5)02458 -> 0258
         ...(6,5)02458 -> 0258
         ...(8,5)0245 -> 025
Intersection 5 in Box8 remove from Row8
         ...(8,2)0359 -> 039
         ...(8,8)0359 -> 039
Intersection 2 in Row5 remove from Box4
         ...(4,1)012456 -> 01456
         ...(4,2)0124567 -> 014567
         ...(6,2)02456 -> 0456
Quads ... 3(2,3,4,6)2 4 5 8 (4,3) (4,4) (4,5) (4,7)
        ... (4,1)01456->016
        ... (4,2)014567->0167
        ... (4,8)0567->067
Y-wing(A2,B4,C5):AB:(4,4) AC:(6,6) BC:(4,7)
        ...(4,5) 0258 -> 028
Y-wing(A2,B4,C5):AB:(4,4) AC:(6,6) BC:(4,7)
        ...(6,7) 0235 -> 023
Y-wing(A2,B4,C5):AB:(4,4) AC:(6,6) BC:(4,7)
        ...(6,8) 0356 -> 036
Intersection 5 in Box5 remove from Row6
         ...(6,2)0456 -> 046
         ...(6,3)0458 -> 048
5 Chains:(4,3)---(4,7) (4,7)---(9,7) (9,7)---(9,2)
     ...(5,2) 0257 -> 027
5 Chains:(4,3)---(4,7) (4,7)---(9,7) (9,7)---(7,8)
     ...(7,3) 0459 -> 049
In rule11 only(4,3)have a 5
In (4,7) only 2 Candidates
In (5,1) only 2 Candidates
In (5,2) only 7 Candidates
In (5,8) only 5 Candidates
In (6,7) only 3 Candidates
In (6,8) only 6 Candidates
In (7,8) only 9 Candidates
In (8,8) only 3 Candidates
In (9,7) only 5 Candidates
In rule2 only(3,8)have a 2
In (2,8) only 4 Candidates
In (3,1) only 4 Candidates
In (4,4) only 4 Candidates
In (4,5) only 8 Candidates
In (4,8) only 7 Candidates
In (6,2) only 4 Candidates
In (6,3) only 8 Candidates
In (6,6) only 5 Candidates
In (7,3) only 4 Candidates
In (8,2) only 9 Candidates
In (8,4) only 2 Candidates
In (8,5) only 5 Candidates
In (8,6) only 4 Candidates
In (9,2) only 3 Candidates
In rule0 only(1,3)have a 9
In rule0 only(1,5)have a 4
In (1,2) only 6 Candidates
In (2,1) only 5 Candidates
In (2,2) only 2 Candidates
In (2,5) only 6 Candidates
In (4,2) only 1 Candidates
In (6,5) only 2 Candidates
In (7,1) only 1 Candidates
In (7,2) only 5 Candidates
In rule3 only(4,1)have a 6

===========
3 6 9 8 4 2 7 1 5
5 2 7 9 6 1 8 4 3
4 8 1 5 3 7 9 2 6
6 1 5 4 8 3 2 7 9
2 7 3 1 9 6 4 5 8
9 4 8 7 2 5 3 6 1
1 5 4 3 7 8 6 9 2
8 9 6 2 5 4 1 3 7
7 3 2 6 1 9 5 8 4

===========