vault backup: 2022-09-08 15:33:54

.obsidian/appearance.json

@@ -1,5 +1,5 @@
 {
-  "theme": "obsidian",
+  "theme": "moonstone",
   "translucency": true,
   "cssTheme": "Prism",
   "interfaceFontFamily": "IBM Plex Sans",

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

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

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