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| # Definition for singly-linked list.
# class ListNode
# attr_accessor :val, :next
# def initialize(val)
# @val = val
# @next = nil
# end
# end
# @param {ListNode} l1
# @param {ListNode} l2
# @return {ListNode}
def add_two_numbers(l1, l2)
n1, n2 = l1, l2
current = answer = ListNode.new(nil)
carry = 0
while n1 || n2 || 0 < carry
a = n1 ? n1.val : 0
b = n2 ? n2.val : 0
x = a + b + carry
carry = x / 10
x -= 10 if 0 < carry
node = ListNode.new(x)
current&.next = node
current = node
n1, n2 = n1&.next, n2&.next
end
answer.next
end
|
