🆘 Algorithms 🆘

A lot of leetcode problems with their most optimal solutions explained in detail!
- The order questions are listed in is on purpose and is recommended to follow

📚Arrays

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Plus One	1	66	Easy	Array	Python / Go / Dart / Rust / Javascript
Two Sum	2	1	Easy	Array, Hash Map	Python / Go / Kotlin / Dart / Rust / Javascript
Valid Parentheses	3	20	Easy	Array, Stack	Python / Go
Maximum Subarray	4	53	Easy	Array	Python / Go / Dart
First Unique Character in a String	5	387	Easy	Array, Hash Map	Python / Go / Javascript / Dart
Move Zeroes	6	283	Easy	Array, Pointer	Python / Go
Find Pivot Index	7	724	Easy	Array, Sliding Window	Python / Go / Kotlin
Best Time to Buy and Sell Stock	8	122	Easy	Array	Python / Go
Shortest Word Distance	9	243	Easy	Array	Python
ZigZag Conversion	10	6	Medium	Array	Python
First Missing Positive	11	41	Hard	Array	Python / Go
Spiral Matrix	12	54	Medium	Array	Python
Sorted Two Sum	13	167	Easy	Array	Python
K-diff Pairs in an Array	14	532	Easy	Array, Hash Map	Python
K Difference Uniqie Pairs	15	-	Easy	Array	Python
Increasing Triplet Subsequence	16	334	Medium	Array	Python
Find First and Last Position of Element in Sorted Array	17	34	Medium	Array, Binary Search	Python
Merge Intervals	18	56	Easy	Array	Python
Valid Sudoku	19	36	Medium	Array, Hash Map	Python
Three Sum	20	-	Medium	Array, Two Sum	Python
Maximum Size Subarray Sum Equals K	21	325	Medium	Array, Two Sum	Python
Product of Array Except Self	22	238	Medium	Array	Python
Trapping Rain Water	23	42	Hard	Array, Two Pointer	Python
Longest Consecutive Sequence	24	128	Hard	Array	Python
Top K Frequent Elements	25	347	Medium	Array, Counting Sort, Hashmap, Heap	Python

Title	Leetcode #	Difficulty	Tags	Solution
First Unique Character in a String	387	Easy	String, Hash Map	Python / Javascript / Dart / Go
Reverse Words in String	344	Easy	String	Python
Reverse Words in String II	557	Easy	String	Python
Strobogrammatic Number	246	Easy	String	Python
Valid Anagram	242	Easy	Hash Map	Python
Compare Version Number	165	Easy	String	Python
String To Integer	8	Medium	String	Python
One Edit Distance	161	Medium	String, Dynamic Programming	Python
Add Binary	67	Easy	String, Recursion	Python
Longest Palindromic Substring	5	Medium	String	Python
Longest Substring Without Repeating Characters	3	Medium	String	Python
Text Justification	68	Hard	String, Scheduling	Python
Minimum Window Substring	76	Hard	String, Sliding Window	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Binary Tree Inorder Traversal	1	94	Easy	Tree, Recursive, Iterative	Python
Insert into a Binary Search Tree	2	-	Easy	Tree	Python
Preorder Traversal	3	-	Easy	Tree traversal	Python
Postorder Traversal	3	-	Medium	Tree traversal	Python
Inorder Successor	4	285	Medium	Tree traversal	Python
Closest Binary Search Tree Value	5	Easy	270	BST Search	Python
Binary Tree Level Order Traversal	6	102	Medium	BFS	Python
Validate Binary Search Tree	7	98	Medium	DFS, Recursion	Python
Same Tree	9	100	Easy	Recursion	Python
Invert Binary Tree	10	226	Easy	Recursion	Python
Symmetric Tree	11	101	Easy	Tree	Python
Univalued Binary Tree	12	965	Easy	Tree	Python
Kth Smallest Element in a BST	13	230	Medium	Tree	Python
Path Sum	14	112	Easy	DFS, Recursion	Python
Minimum Depth of Binary Tree	15	111	Easy	Tree	Python
Sum Root to Leaf Numbers	16	129	Medium	DFS, Recursion	Python
Flatten Binary Tree to Linked List	17	114	Medium	Recursion	Python
Convert BST to Greater Tree	18	538	Easy	BFS	Python
Binary Tree Zigzag Level Order Traversal	19	103	Medium	BFS	Python
Populating Next Right Pointers in Each Node	20	116	Medium	BFS	Python
Binary Tree Maximum Path Sum	21	124	Hard	DFS, Recursion	Python
Delete Nodes And Return Forest	22	1110	Medium	DFS, Recursion	Python
Binary Search Tree to Greater Sum Tree	23	1038	Medium	In Order	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Reverse Linked List	1	206	Easy	Linked List	Python
Merge Linked List	2	-	Easy	Linked List, Recursion	Python
Add Two Numbers	3	2	Medium	Linked List	Python
Delete Node From Linked List	4	237	Easy	Linked List	Python
Merge k Sorted Lists	5	23	Hard	Linked List, Heap	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Decode String	1	394	Medium	Stack	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Meeting Rooms II	1	253	Medium	Heap	Python

Title	Leetcode #	Difficulty	Tags	Solution
Number of 1 Bits	191	Easy	Bitwise	Python / C
Hamming Distance	461	Easy	Bitwise	Python
Single Number	91	Easy	Bitwise	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Number Of Islands	1	200	Medium	Depth First Search	Python / C
Flood Fill	2	733	Easy	Depth First Search	Python
Graph Valid Tree	3	261	Easy	Graph	Python
Number of Connected Components in an Undirected Graph	4	323	Medium	Depth First Search	Python
Topological Sort	5	-	Medium	Graph	Python
Validate DAG	6	-	Medium	Graph	Python
Redundant Connection	7	684	Medium	Graph	Python
Course Schedule	8	207	Medium	Top Sort	Python
Course Schedule II	9	210	Medium	Top Sort	Python

Title	Leetcode #	Difficulty	Tags	Solution
Merge Sort	-	Easy	Sorting, Recursion	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Find First and Last Position of Element in Sorted Array	1	34	Medium	Binary Search	Python
Search in Rotated Sorted Array	2	33	Medium	Binary Search	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Pow(x, n)	1	50	Medium	Divide and Conquer, Recursion	Python
Number of Inversions	-	-	Medium	Divide and Conquer	Python
Majority Element	-	-	Medium	Divide and Conquer	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
Climbing Stairs	1	70	Easy	Dynamic Programming	Python
Coin Change 2	2	518	Medium	Dynamic Programming	Python
Decode Ways	3	91	Medium	Dynamic Programming, Top Down	Python
Unique Paths	4	62	Medium	Dynamic Programming, Top Down	Python
Delete Operation for Two Strings	5	583	Medium	Dynamic Programming	Python
Edit Distance	6	72	Hard	Dynamic Programming, Top Down	Python
Longest Common Subsequence	7	1143	Hard	Dynamic Programming, Bottom Up	Python
Maximum Length of Repeated Subarray	8	718	Medium	Dynamic Programming, Bottom Up, Longest Common Subarray	Python

Title	Recommended Order #	Leetcode #	Difficulty	Tags	Solution
LRU Cache	1	146	Medium	Linked List, Hashmap	Python