難度: 中等php
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 contain a single digit. Add the two numbers and return it as a linked list.html
You may assume the two numbers do not contain any leading zero, except the number 0 itself.node
給出兩個 非空
的鏈表用來表示兩個非負的整數。其中,它們各自的位數是按照 逆序
的方式存儲的,而且它們的每一個節點只能存儲 一位 數字。
若是,咱們將這兩個數相加起來,則會返回一個新的鏈表來表示它們的和。
您能夠假設除了數字 0 以外,這兩個數都不會以 0 開頭。git
示例:this
輸入:(2 -> 4 -> 3) + (5 -> 6 -> 4)
輸出:7 -> 0 -> 8
緣由:342 + 465 = 807
spa
這個題目至關因而兩個鏈表進行相加,把鏈表每一節點的值存到新鏈表對應的節點,涉及到進位。3d
/** * Definition for a singly-linked list. * class ListNode { * public $val = 0; * public $next = null; * function __construct($val) { $this->val = $val; } * } */ class Solution { /** * @param ListNode $l1 * @param ListNode $l2 * @return ListNode */ function addTwoNumbers($l1, $l2) { $add_flag = 0; $result_list = new ListNode(0); $curr = $result_list; //指向當前鏈表 do { $val = $l1->val + $l2->val + $add_flag; if ($val >= 10) { $add_flag = 1; $val -= 10; //減去,由於進位了 } else { $add_flag = 0; } $tmp_list = new ListNode($val); $curr->next = $tmp_list; $curr = $curr->next; $l1 = $l1->next; $l2 = $l2->next; } while ($l1 || $l2 || $add_flag); return $result_list->next; } }
運行結果: code
PHP鏈表打印出來的結構:htm
ListNode Object ( [val] => 0 [next] => ListNode Object ( [val] => 7 [next] => ListNode Object ( [val] => 0 [next] => ListNode Object ( [val] => 8 [next] => ) ) ) )
連接:https://leetcode-cn.com/problems/add-two-numbers/blog
一、PHP 鏈表的使用 - 簡書
https://www.jianshu.com/p/e409ec512caa 二、2. Add Two Numbers · leetcode https://leetcode.wang/leetCode-2-Add-Two-Numbers.html