1 
     next;15         }16 17         $j = 1;18         $cnode = $head;19         while ($j < $n - $i) {20             $j++;21             $cnode = $cnode->next;22         }23 24         return $cnode;25     }26 27     #第二种方法，使用两个指针同时移动28     function last_i_2($head, $i) {29         $p1 = $head;30         $p2 = $head;31         $k = 0;32 33         while ($k < $i) {34             $p1 = $p1->next;35             $k++;36         }37 38         while (($p1 = $p1->next) != null) {39             $p2 = $p2->next;40         }41 42         return $p2;43     }44 45     $head = new Node();46     $n1 = new Node();47     $n2 = new Node();48     $n3 = new Node();49     $n4 = new Node();50     $head->data = 0;51     $n1->data = 1;52     $n2->data = 2;53     $n3->data = 3;54     $n4->data = 4;55     $head->next = $n1;56     $n1->next = $n2;57     $n2->next = $n3;58     $n3->next = $n4;59 60     echo last_i($head, 2)->data . "
";61     echo last_i_2($head, 2)->data;62 ?>

2

2