LeetCode 2 Add Two Numbers

You are given two linked lists representing two non-negative numbers. 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.

Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8

 

 

# 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)
    return l1 if l2.nil?

 

return l2 if l1.nil?

s1 = Array.new s2 = Array.new n = Array.new while l1 s1.unshift(l1.val) l1 = l1.next end while l2 s2.unshift(l2.val) l2 = l2.next end x = s1.join.to_i+s2.join.to_i n = x.to_s.chars.map(&:to_i) ans = ListNode.new(0) d = ans l = n.length() l.times do d.next = ListNode.new(n.pop) d = d.next end ans.next end