This problem took me 3 hours lol

Author: tech-cow

README.md

@@ -18,4 +18,5 @@ Success is like pregnancy, Everybody congratulates you but nobody knows how many
 |203|[Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/#/description) | [Python](./linkedlist/RemoveLinkedListElements.py) | _O(n)_| _O(1)_  | Easy || |
 |206|[Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/#/description) | [Python](./linkedlist/ReverseLinkedList.py) | _O(n)_| _O(1)_  | Easy |CC189| [Video Tutorial](https://www.youtube.com/watch?v=sYcOK51hl-A&t=681s) |
 |234|[Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/) | [Python](./linkedlist/palindrome.py) | _O(n)_| _O(1)_  | Easy |CC189| Two Pointers|
-|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/#/description) | [Python](./linkedlist/addTwoNumbers.py) | _O(n)_| _O(n)_  | Medium |CC189| ||
+|2|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers/#/description) | [Python](./linkedlist/addTwoNumbers.py) | _O(n)_| _O(n)_  | Medium |CC189| |
+|445| [Add Two Numbers II](https://leetcode.com/problems/add-two-numbers-ii/#/description)| [Python](./linkedlist/addTwoNumbersTwo.py) | _O(n)_| _O(n)_  | Medium |CC189 |Stack|

linkedlist/addTwoNumbersTwo.py

@@ -0,0 +1,121 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Author: Yu Zhou
+# You are given two non-empty linked lists representing two non-negative integers. The most significant digit comes first and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
+# Example:
+# Input: (7 -> 2 -> 4 -> 3) + (5 -> 6 -> 4)
+# Output: 7 -> 8 -> 0 -> 7
+
+# ****************
+# Final Solution *
+# Using Stack    *
+# ****************
+# Definition for singly-linked list.
+# class ListNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.next = None
+
+class Solution(object):
+    def addTwoNumbers(self, n1, n2):
+       l1 = self.list_to_stack(n1)
+       l2 = self.list_to_stack(n2)
+       stack = self.add_helper(l1,l2)
+       return self.stack_to_list(stack)
+
+    def list_to_stack(self, node):
+        stack = []
+        while node:
+            stack.append(node.val)
+            node = node.next
+        return stack
+
+    def add_helper(self, s1, s2):
+        res = []
+        carry = 0
+        while s1 or s2 or carry:
+            num1 = s1.pop() if s1 else 0
+            num2 = s2.pop() if s2 else 0
+            total = num1 + num2 + carry
+            res.append(total % 10)
+            carry = total/10
+        return res
+
+    def stack_to_list(self, stack):
+        head = ListNode(0)
+        cur = head
+        while stack:
+            cur.next = ListNode(stack.pop())
+            cur = cur.next
+        return head.next
+
+
+# *****************************************
+# The following code is an fail attempt   *
+# Passed 893/1539 Test Cases              *
+# Failed Cases such as 1 + 99(Getting 01) *
+# *****************************************
+class Solution(object):
+    def addTwoNumbers(self, n1, n2):
+        #Pad The Two List
+        len1, len2 = self.get_length(n1), self.get_length(n2)
+        if len1 > len2:
+            #Insert Dummy Node to head
+            for _ in range(len1-len2):
+                temp = ListNode(0)
+                temp.next = n2
+                n2 = temp
+        else:
+            for _ in range(len2-len1):
+                temp = ListNode(0)
+                temp.next = n1
+                n1 = temp
+
+        has_carry_head = False
+        #Edge: Largest Carry
+        res = cur = ListNode(0)
+        guard1, guard2 = n1, n2
+        carry = 0
+        while n1 or n2 or carry:
+            if n1.next and n2.next:
+                carry = (n1.next.val + n2.next.val) / 10
+            result = carry + n1.val + n2.val
+            temp = ListNode(result % 10)
+            front_carry = result / 10
+            cur.next = temp
+            cur = cur.next
+
+            n1 = n1.next
+            n2 = n2.next
+
+        if guard1.val + guard2.val + front_carry > 10:
+            res.val = 1
+            has_carry_head = True
+
+        print has_carry_head
+        return res if has_carry_head else res.next
+
+    def display(self,node):
+        cur = node
+        arr = []
+        while cur:
+            arr.append(cur.val)
+            cur = cur.next
+        print arr
+
+    def get_length(self, node):
+        cur = node
+        count = 0
+        while cur:
+            count += 1
+            cur = cur.next
+        return count
+
+#失败心经
+# 讲道理，现在还是懵的。。首先insert方程和pad方程
+# 若是单独写一个方程，然后带入，不知道为什么不能pass by reference
+# 所以后来很机械化的没有写进方程
+# 这个代码大部分的Test Case都能过，有一些小的，是在不知道怎么调了
+# 因为弄得特别的乱，大概思路就是Pad两个List，然后加减，CC189的套路
+# 这道题后来看了答案，可以用Stack来写。

linkedlist/ll.py

@@ -0,0 +1,107 @@
+#!/usr/bin/python
+#coding:utf-8
+#=======================================================================
+#  Author: Yu Zhou
+#  Singly Linked List
+#=======================================================================
+from random import randint
+
+class Node(object):
+#Constructor
+def __init__(self, val, next = None):
+    self.val = val
+    self.next = next
+
+class LinkedList(object):
+#Constructor
+def __init__(self, head = None, size = None):
+    self.head = head
+    self.size = size
+
+#Display
+def __str__(self):
+    res = []
+    cur = self.head
+    while cur:
+        res.append(str(cur.val))
+        cur = cur.next
+    return ' -> '.join(res)
+
+
+
+#在头Insert
+def insert_head(self, val):
+    if self.head == None:
+        self.head = Node(val)
+    else:
+        temp = Node(val) #创建Temp Node
+        temp.next = self.head  #指向Head
+        self.head = temp #把head的reference改到这个Temp Node
+
+#在末尾Insert
+def insert_tail(self, val):
+    if self.head == None:
+        self.head = Node(val)
+    else:
+        cur = self.head
+        temp = Node(val)
+        while cur.next:  #位移
+            cur = cur.next
+        cur.next = temp
+
+#Generate Insert 10位数
+def generate(self):
+    for _ in xrange(10):
+        self.insert_tail(randint(0,9))
+
+#Insert自定义多位数
+def insert_multiple(self, val):
+    for v in val:
+        self.insert_tail(v)
+
+#Search
+def search(self, val):
+    if self.head == None:
+        raise ValueError("List is empty")
+
+    cur = self.head
+    while cur:
+        if cur.val == val:
+            return True
+        else:
+            cur = cur.next
+    return False
+
+#Delete V1 using Prev
+def delete_1(self, val):
+    if self.head == None:
+        return self.head
+
+    cur = self.head
+    prev = None
+
+    while cur:
+        if cur.val == val:
+            if prev:
+                prev.next = cur.next
+            else:
+                self.head = cur.next
+        prev = cur
+        cur = cur.next
+
+#Delete V2 not using Prev
+def delete_2(self, val):
+    if self.head == None:
+        return self.head
+
+    cur = self.head
+    #Edge case
+    if cur.val == val:
+        self.head = cur.next
+
+    #The rest
+    while cur.next:
+        if cur.next.val == val:
+            cur.next = cur.next.next
+        else:
+            cur = cur.next