php - Add Two Numbers

php - Add Two Numbers

今天用php來改寫吧! Let’s Go!!!

題目為


You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order, and each of their nodes contains a single digit. Add the two numbers and return the sum as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example 1 :

Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Explanation: 342 + 465 = 807.

Example 2 :

Input: l1 = [0], l2 = [0]
Output: [0]

Example 3 :

Input: l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
Output: [8,9,9,9,0,0,0,1]

解法

  1. 實際解法

    /**
* Definition for a singly-linked list.
* class ListNode {
*     public $val = 0;
*     public $next = null;
*     function __construct($val = 0, $next = null) {
*         $this->val = $val;
*         $this->next = $next;
*     }
* }
*/
class Solution {


   /**
    * @param ListNode $l1
    * @param ListNode $l2
    * @return ListNode
    */
   function addTwoNumbers($l1, $l2) {
       return  $this->calculation($l1,$l2,0);
   }


      /**
    * @param ListNode $l1
    * @param ListNode $l2
    * @param int $carry
    * @return ListNode
    */
   function calculation($l1, $l2 , $carry= 0) {
           if ($l1 == null && $l2 == null && $carry == 0) {
                return null;
           }


           if ($l1 == null) {
               $l1 = new ListNode(0, null);
           }

           if ($l2 == null) {
               $l2 = new ListNode( 0,  null);
           }

           $val = $l1->val + $l2->val + $carry;
           $carry = intval(floor($val / 10));
       	return new ListNode($val % 10,$this->calculation($l1->next, $l2->next, $carry));
       }

}

  2. 執行效能

碎碎念

沒想到 php 的效能也比 C# 好，但是也沒有贏過 golang ~~~ 一樣都是遞迴寫法，沒想到差得比我想的還要多一點。 再來用 TypeScript 寫寫看囉!

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