[python/연결리스트] leetcode - Add Two Numbers 문제

leetcode 문제 : https://leetcode.com/problems/add-two-numbers/

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution(object):
    def addTwoNumbers(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        num1,num2,total = 0,0,0
        i,j = 0,0
        
        while(l1):
            num1 += l1.val *(10 ** i)
            i += 1
            l1 = l1.next
        
        while(l2):
            num2 += l2.val *(10 ** j)
            j += 1
            l2 = l2.next
        
        total = num1 + num2
        sum_list = list(map(int, str(total)))
        
        last = None
        for num in sum_list:
            node = ListNode(num)
            node.next = last
            last = node
        
        return node

1568 / 1568 test cases passed.	Status:  Accepted
Runtime: 87 ms Memory Usage: 13.5 MB	Submitted: 7 hours, 4 minutes ago

 

best 풀이 

 

class Solution(object):
    def addTwoNumbers(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        result = ListNode(0)
        result_tail = result
        carry = 0
                
        while l1 or l2 or carry:            
            val1  = (l1.val if l1 else 0)
            val2  = (l2.val if l2 else 0)
            carry, out = divmod(val1+val2 + carry, 10)    
                      
            result_tail.next = ListNode(out)
            result_tail = result_tail.next                      
            
            l1 = (l1.next if l1 else None)
            l2 = (l2.next if l2 else None)
               
        return result.next

 

완벽히 이해가..ㅜ

 

연결리스트 python 참고 : https://goforit.tistory.com/145