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58 lines
1.5 KiB
Plaintext
58 lines
1.5 KiB
Plaintext
---
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title: '2. Add Two Numbers'
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description: 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
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sidebar:
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label: 'Add Two Numbers'
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badge: 'Medium'
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---
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<Badge variant="accent">Hybrid Structures</Badge>
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### Example 1:
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- Input: `l1 = [2,4,3], l2 = [5,6,4]`
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- Output: `[7,0,8]`
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- Explanation: `342 + 465 = 807`.
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### Example 2:
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- Input: `l1 = [0], l2 = [0]`
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- Output: `[0]`
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### Example 3:
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- Input: `l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]`
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- Output: `[8,9,9,9,0,0,0,1]`
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### Constraints:
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- The number of nodes in each linked list is in the range [1, 100].
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- `0 <= Node.val <= 9`
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- It is guaranteed that the list represents a number that does not have leading zeros.
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## Solution
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```py
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# Definition for singly-linked list.
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# class ListNode:
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# def __init__(self, val=0, next=None):
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# self.val = val
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# self.next = next
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class Solution:
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def addTwoNumbers(
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self, l1: Optional[ListNode], l2: Optional[ListNode]
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) -> Optional[ListNode]:
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dummy = ListNode()
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carry = 0
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curr = dummy
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while l1 or l2 or carry:
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s = (l1.val if l1 else 0) + (l2.val if l2 else 0) + carry
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carry, val = divmod(s, 10)
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curr.next = ListNode(val)
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curr = curr.next
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l1 = l1.next if l1 else None
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l2 = l2.next if l2 else None
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return dummy.next
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```
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