From 484bcdf9154707407ad08c2b869dcd015d64912e Mon Sep 17 00:00:00 2001
From: juan <juancloudcomputing@protonmail.com>
Date: Thu, 8 Sep 2022 15:33:54 +0800
Subject: [PATCH] vault backup: 2022-09-08 15:33:54

---
 .obsidian/appearance.json                  |  2 +-
 OJ notes/OJ-index.md                       |  6 ++
 OJ notes/pages/Elementary Math Problems.md | 22 ++++++
 OJ notes/pages/Leetcode Add-Two-Numbers.md | 79 ++++++++++++++++++++++
 4 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 OJ notes/pages/Elementary Math Problems.md
 create mode 100644 OJ notes/pages/Leetcode Add-Two-Numbers.md

diff --git a/.obsidian/appearance.json b/.obsidian/appearance.json
index 0f1a331..d9941ff 100644
--- a/.obsidian/appearance.json
+++ b/.obsidian/appearance.json
@@ -1,5 +1,5 @@
 {
-  "theme": "obsidian",
+  "theme": "moonstone",
   "translucency": true,
   "cssTheme": "Prism",
   "interfaceFontFamily": "IBM Plex Sans",
diff --git a/OJ notes/OJ-index.md b/OJ notes/OJ-index.md
index 06a96b4..d28f688 100644
--- a/OJ notes/OJ-index.md	
+++ b/OJ notes/OJ-index.md	
@@ -15,6 +15,12 @@ This is where I store notes about CS
 
 ## Lists
 
+#### Collection of problems of same kind
+
+```query
+#problem_collection 
+```
+
 #### TODO
 
 ```query
diff --git a/OJ notes/pages/Elementary Math Problems.md b/OJ notes/pages/Elementary Math Problems.md
new file mode 100644
index 0000000..356d194
--- /dev/null
+++ b/OJ notes/pages/Elementary Math Problems.md	
@@ -0,0 +1,22 @@
+# Elementary Math Problems
+
+2022-09-08 15:23
+
+#math
+#algorithm 
+#problem_collection
+
+These are problems solved by re-implementing elementary 
+math:
+
+### Add
+
+[[Leetcode Add-Strings]]
+[[Leetcode Add-Two-Numbers]]
+
+### Minus
+
+### Multiply
+
+
+### Divide
\ No newline at end of file
diff --git a/OJ notes/pages/Leetcode Add-Two-Numbers.md b/OJ notes/pages/Leetcode Add-Two-Numbers.md
new file mode 100644
index 0000000..0c71370
--- /dev/null
+++ b/OJ notes/pages/Leetcode Add-Two-Numbers.md	
@@ -0,0 +1,79 @@
+# Leetcode Add-Two-Numbers
+
+2022-09-08 15:22
+
+> ##### Algorithms:
+>
+> #algorithm #math
+>
+> ##### Data structures:
+>
+> #DS #linked_list 
+>
+> ##### Difficulty:
+>
+> #coding_problem #difficulty_medium
+>
+> ##### Additional tags:
+>
+> #leetcode 
+>
+> ##### Revisions:
+>
+> N/A
+
+##### Links:
+
+- [Link to problem](https://leetcode.com/problems/add-two-numbers/)
+
+---
+
+### Problem
+
+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.
+
+You may assume the two numbers do not contain any leading zero, except the number 0 itself.
+
+#### Examples
+
+**Example 1:**
+
+![](https://assets.leetcode.com/uploads/2020/10/02/addtwonumber1.jpg)
+
+```
+**Input:** l1 = [2,4,3], l2 = [5,6,4]
+**Output:** [7,0,8]
+**Explanation:** 342 + 465 = 807.
+```
+
+**Example 2:**
+
+```
+**Input:** l1 = [0], l2 = [0]
+**Output:** [0]
+```
+
+**Example 3:**
+
+```
+**Input:** l1 = [9,9,9,9,9,9,9], l2 = [9,9,9,9]
+**Output:** [8,9,9,9,0,0,0,1]
+```
+
+#### Constraints
+
+-   The number of nodes in each linked list is in the range `[1, 100]`.
+-   `0 <= Node.val <= 9`
+-   It is guaranteed that the list represents a number that does not have leading zeros.
+
+### Thoughts
+
+> [!summary]
+> This is a elementary #math problem.
+> For a list of similar questions, visit [[Elementary Math Problems]]
+
+Done by using elementary math.
+
+Use only one 
+
+### Solution