vault backup: 2022-06-15 22:53:24

CS notes/CS-index.md

@@ -12,6 +12,28 @@
 This is where I store notes about CS
 
 ___
+
+## Lists
+- Needs more understandings #CS_list_need_understanding
+```expander
+tag:#CS_list_need_understanding 
+- [ ] [[$filename]]
+```
+ 
+- [ ] [[Leetcode Reverse-Linked-List]]
+ 
+
+
+- Needs practicing #CS_list_need_practicing
+```expander
+tag:#CS_list_need_practicing 
+- [ ] [[$filename]]
+```
+ 
+- [ ] [[Leetcode Reverse-Linked-List]]
+ 
+
+
 ## Websites
 
 #### [leetcode.com](https://leetcode.com)
@@ -32,6 +54,7 @@ tag:#leetcode
 - [[Leetcode Ransom-Note]]
 - [[Leetcode Remove-Linked-List-Elements]]
 - [[Leetcode Reshape-The-Matrix]]
+- [[Leetcode Reverse-Linked-List]]
 - [[Leetcode Search-a-2D-Matrix]]
 - [[Leetcode Two-Sum]]
 - [[Leetcode Valid-Anagram]]
@@ -121,5 +144,13 @@ tag:#algorithm tag:#CS_analysis -tag:#template_remove_me
 - [[$filename]]
 ```
  
+- [[Binary Search Algorithm]]
+- [[Binary Search Algorithm.sync-conflict-20220615-121016-T44CT3O]]
+- [[cpp_std_sort]]
+- [[Floyd's Cycle Finding Algorithm]]
+- [[Kadane's Algorithm]]
+- [[Two pointers approach]]
+ 
+
 
  

CS notes/pages/Leetcode Reverse-Linked-List.md

@@ -9,6 +9,8 @@
 #DS #linked_list 
 ##### Difficulty:
 #leetcode  #coding_problem #difficulty-easy 
+##### Lists:
+#CS_list_need_understanding #CS_list_need_practicing 
 ##### Related topics:
 ```expander
 tag:#linked_list
@@ -53,7 +55,29 @@ Given the `head` of a singly linked list, reverse the list, and return _the reve
 
 ### Thoughts
 
-> [!summary]
+I thought a slow O(n ^ 2) hybrid solution, while there are better algorithms, using in-place insert, or recursion.
-> This is a #template_remove_me
+
+The in place insert is easier to understand, and simple to implement, using a very clever trick.
 
 ### Solution
+I've referred to this guy: https://leetcode.com/problems/reverse-linked-list/discuss/58130/C%2B%2B-Iterative-and-Recursive
+
+```cpp
+class Solution {
+public:
+  ListNode *reverseList(ListNode *head) {
+    ListNode *pre = new ListNode(0), *cur = head;
+    // pre is before head, and insert any element after pre.
+    pre->next = head;
+    while (cur && cur->next) {
+      // Move cur->next after pre.
+      ListNode *temp = pre->next;
+      pre->next = cur->next;
+      cur->next = cur->next->next;
+
+      pre->next->next = temp;
+    }
+    return pre->next;
+  }
+};
+```

_templates/OJ Problem Notes.md

@@ -2,13 +2,18 @@
 
 #### {{date}} {{time}}
 
----
+> ##### Algorithms:
-##### Algorithms:
+> #algorithm 
-#algorithm 
+> ##### Data structures:
-##### Data structures:
+> #DS
-#DS
+> ##### Difficulty:
-##### Difficulty:
+> #coding_problem #difficulty-easy 
-#<CHANGE_ME> #coding_problem #difficulty-easy 
+> ##### Additional tags:
+> #<platforms-like-leetcode> #<list-to-be-added>
+> ##### Revisions:
+> Initial encounter: {{date}}
+> 1st revision: <use-template-command-to-insert-date>
+
 ##### Related topics:
 ```expander
 tag:#<INSERT_TAG_HERE>

_templates/cpp_stuff_explainer.md

@@ -2,13 +2,15 @@
 
 #### {{date}} {{time}}
 
-___
+> ##### Algorithms:
-##### Algorithms:
+> #algorithm 
-#algorithm 
+> ##### Data structures:
-##### Data structures:
+> #DS
-#DS
+> ##### Difficulty:
-##### Difficulty:
+> #CS_analysis #difficulty-
-#CS_analysis #difficulty-
+> ##### Additional tags:
+> 
+
 ##### Related problems:
 ```expander
 tag:#coding_problem tag:#<CHANGE_ME> -tag:#template_remove_me