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]
Constraints:
- The number of nodes in each linked list is in the range
[1, 100]
. 0 <= Node.val <= 9
- It is guaranteed that the list represents a number that does not have leading zeros.
题目大意:
数位链表(从最低位到最高位)相加
算法思路:
类似于merge sort
注意事项:
- 其中一个可能较长,所以主循环出来后还要继续循环较长的链表,类似于merge sort
- 所有链表遍历完后,carry可能还会是1,要加一个if语句特别处理
Python代码:
1 | def addTwoNumbers(self, l1: 'ListNode', l2: 'ListNode') -> 'ListNode': |
算法分析:
时间复杂度为O(n + m)
,空间复杂度O(1)