The implementation of the linked list in PHP

This article introduces the content of the link list in PHP implementation, has a certain reference value, now share to everyone, the need for friends can refer to

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Today write code changed a font, used to look good console , today found a more like style Source Code Pro
On two pictures, it is very good-looking!!!

Step into the line and talk about the operation of the list

Node

• First, you have to have a node class for storing data

<?phpnamespace linkedlist;class node{    /**     * @var $data integer     */public    $data;    /**     * Node points to the next element     *     * @var $next node */public    $next;    Public function __construct (int $data =-1)    {public        function __construct (int $data = null)        {            //Initialize Assignment The value data can also be obtained by $node->data = X; Assignment            $this->data = $data;        }}

Linked list management class (for manipulating node data)

• The code of the Operation class is too long for us to parse in part

Header insertion (because it's relatively simple, so let's say this first)

• If you listen to a name, you're going to insert a node from the head.

• Initializes the current node when the linked list is empty

• When the linked list is not empty, the new node is used as the head junction.

Public function inserthead (int $data): bool{//////////////////////////////////////////////////////////////////////           /////    // +-----------+    +--------+    +--------+    // |    |        |    |        |    | // | Head Node |  +> | Node |  +> | Node |           +>//|  | |        |  | |        |    | |           // |  | |        |  | |        |    | |    // |  Next | |  |  Next | |  |    Next | |  // +------+----+ |  +----+---+ |    +----+---+ |      //        |       |     |       |     |    |                   //        +------+       +-----+       +-----+    ///////////////////////////////////////////////////////////////    //           +-----------+    +--------+    +--------+    //                   |    |        |    |        |    | +---> | Head Node |  +> | Node |  +> | Node |     +>//|           |  | |        |  | |        |    | |     //             |           |  | |        |  | |        |    | |//             |    |  Next | |  |  Next | |  |    Next | |     //             |  +------+----+ |  +----+---+ |    +----+---+ |            //             |      |       |     |       |     |    |            //  +--------+ |        +------+       +-----+       +-----+    //  |    | |    |new node| |        //  |    | |        //  |    | |  //  |    Next | |    //  +----+---+ |     //       |    | +-----+////1. Instantiate a data node//2. Causes the current node's next equal to the present head node//Even if the current head node is NULL, it can also be set up//3.    Make the current Node a head node//To complete the insertion of the head node $newNode = new node ($data);    $newNode->next = $this->head;    $this->head = $newNode; return true;}

Insert the node (index=0 is the head node, go down, and return False if the position is exceeded)

Public function Insert (int $index = 0, int $data): bool{//Head node insertion, when header does not exist, or index 0 if (is_null ($this->head) | | $i    Ndex = = 0) {return $this->inserthead ($data);    }//Normal node insertion, index calculated starting from 0//skipping head node, starting from 1 $currNode = $this->head;    $startIndex = 1; Traversing the entire list, if the current node is null, represents the next end of the trailer, Exits the loop for ($currIndex = $startIndex;! is_null ($currNode); + + $currIndex) {//     //////////////////////////////////////////////////////////////////////////        ///        //   +--------+    +--------+        +-------------+    +--------+        //   |    |        |    |             |    |        |        |  //   | Node | +> |currnode| +> |currnode next|  +> | Node |        +>//|  | |        |  | |             |  | |        |        | |        //   |  | |        |  | |             |  | |        |        | |  //   |  Next | |  |  Next | |     |  Next | |  |        Next | |  //   +----+---+ |  +----+---+ |  +------+------+ | +----+---+ |     //        |       |     |         |        |       |     |        | //        +-----+       +-----+         +--------+       +-----+        //////////////////////////////////////////////////         //////////////////////////        //   +--------+    +--------+                +-------------+    +--------+        //   |    |        |                |             |    |        |        |  //   | Node |             +> |currnode| +> |currnode next|  +> | Node |        +>//|  | |        |             |  |             |  | |        |        | |        //   |  | |        |             |  |             |  | |        |        | |  //   |  Next | |  |             Next |  |     |  Next | |  |        Next | |  //   +----+---+ |  +--------+             |  +------+------+ |        +----+---+ |     //        |              |         +--------+ |        |       |     |        |        //        +-----+              |         | | +--------+       +-----+       |new node| |        //                             |        | |        //                             |        | |  //                             |        Next | |        //                             +----+---+ |     //                                  |        | //                                  +-----+        ///////////////////////////////////////////////////////////////////////        /////        //        //   +--------+    +--------+                +-------------+    +--------+        //   |    |        |                |             |    |        |        |  //   | Node |             +> |currnode| +> |currnode next|  +> | Node |        +>//|  | |        |             |  |             |  | |        |        | |        //   |  | |        |             |  |             |  | |        |        | |  //   |  Next | |  |             Next |  |     |  Next | |  |        Next | |  //   +----+---+ | +----+---+             |  +------+------+ |        +----+---+ |     //        |       |      |         +--------+ |        |       |     |        |      //        +-----+       |        |         | |        +--------+ +-----+//+----> |new node| |        //                             |        | |        //                             |        | |  //                             |        Next | |        //                             +----+---+ |     //                                  |        | +-----+////1. The current index equals the index of the incoming parameter//2. Instantiate the new data node//3. The next node of the new node that points to the current node//4.            The next node of the current node points to the new node if ($currIndex = = = $index) {$newNode = new node ($data);            $newNode->next = $currNode->next;            $currNode->next = $newNode;        return true;    }//move to the next node $currNode = $currNode->next; } return false;}

Above two this is the basic operation of inserting. Take a look at the code for the instance.

<?php//automatically loaded code is not posted, directly in the Githubrequire __dir__. ' /.. /vendor/bootstrap.php ';//Instantiate a list of managed objects $manager = new \linkedlist\manager ();//8$manager->inserthead (8);//5 8$ Manager->inserthead (5);//1 5 8$manager->inserthead (1);//1 2 5 8$manager->insert (1, 2);//False node element less than 6 $manag Er->insert (5, 4);//1 2 5 8 9$manager->insertend (9);//3$manager->find (8);//1 2 8 9$manager->delete (2);

Find

• Finding the value of a linked list is also straightforward, as long as you traverse it

/*** Index found in the value of the linked list * Successfully returned index value, cannot find return -1** @param int $data * @return int*/public function find (int $data): int{    $currNode = $this->head;    Find or is very simple, as long as the list is traversed once, and then determine whether the value is equal to the for    ($i = 0;! is_null ($currNode); + + $i) {        if ($currNode->data = = = $data) {            return $i;        }        $currNode = $currNode->next;    }    return-1;}

• Only need to traverse the list once, find the equal value, find the return index value, can't find return-1

Delete

/** * Delete Linked list node * * @param int $index * @return bool */public function Delete (int $index): bool{    //No nodes, skip directly    if (Is_null ($this->head)) {       return false;    } ElseIf ($index = = = 0) {        //Head node deletion        $this->head = $this->head->next;    }    The starting index here is 1    //But the current node points to the exact head node/    /Because the deletion must be marked by the deletion of the previous nodes    //For the judge is to determine whether the next node is null    //$currNode is the node of the operation    //    $currNode->next is the node to be removed    $startIndex = 1;    $currNode = $this->head;    for ($i = $startIndex; Is_null ($currNode->next); + + $i) {        if ($index = = = $i) {            //make the current node equal to the next            //of the node to be deleted You can complete the deletion            $currNode->next = $currNode->next->next;            break;        }        $currNode = $currNode->next;    }    return true;}

End

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