Blind 75 Leetcode Problem to crack DSA Interview.

Preparing for an interview and need to brush up on Data Structures and Algorithms (DSA) quickly? I've got you covered with an efficient strategy: Blind 75. Here's how it works:

Practice with Purpose: Solve 75 carefully selected LeetCode problems, ranging in difficulty, over a few weeks.

Daily Commitment: Spend some time each day tackling these problems, gradually building your skills.

Comprehensive Coverage: The chosen problems cover a wide range of DSA concepts, helping you understand them better.

It's that simple. With Blind 75, you'll be well-prepared for any DSA interview challenge. Ready to dive in and excel?

Week 1

#	Question	Notes	Difficulty
1	Two Sum	Use a hashmap to store complements of each element.	Easy
2	Valid Parentheses	Use a stack to keep track of open parentheses.	Easy
3	Merge Two Sorted Lists	Merge lists recursively or iteratively.	Easy
4	Best Time to Buy and Sell Stock	Keep track of minimum price and maximum profit.	Easy
5	Valid Palindrome	Use two pointers approach.	Easy
6	Invert Binary Tree	Swap left and right child recursively.	Easy
7	Valid Anagram	Count characters or sort and compare strings.	Easy
8	Binary Search	Implement binary search algorithm.	Easy
9	Flood Fill	Use depth-first search or breadth-first search.	Easy
10	Lowest Common Ancestor of a Binary Search Tree	Traverse the tree recursively or iteratively.	Easy
11	Balanced Binary Tree	Check the height difference of left and right subtrees.	Easy
12	Linked List Cycle	Use two pointers approach.	Easy
13	Implement Queue using Stacks	Implement enqueue and dequeue using two stacks.	Easy

Week 2: Transition from Easy to Medium

#	Question	Notes	Difficulty
14	First Bad Version	Use binary search to find the first bad version.	Easy
15	Ransom Note	Use a hashmap to store characters in the magazine.	Easy
16	Climbing Stairs	Use dynamic programming to solve.	Easy
17	Longest Palindrome	Count characters to form a palindrome.	Easy
18	Reverse Linked List	Iteratively reverse the linked list.	Easy
19	Majority Element	Use Boyer-Moore Voting Algorithm.	Easy
20	Add Binary	Use bitwise operations.	Easy
21	Diameter of Binary Tree	Calculate the height of the left and right subtrees.	Easy
22	Middle of the Linked List	Use two pointers approach.	Easy
23	Maximum Depth of Binary Tree	Use depth-first search.	Easy
24	Contains Duplicate	Use a hashmap to check duplicates.	Easy
25	Maximum Subarray	Use Kadane’s Algorithm.	Medium

Week 3: Medium

#	Question	Notes	Difficulty
27	01 Matrix	Use breadth-first search or dynamic programming.	Medium
28	K Closest Points to Origin	Use a priority queue or quickselect algorithm.	Medium
29	Longest Substring Without Repeating Characters	Use a sliding window approach.	Medium
30	3Sum	Use two pointers or hashing.	Medium
31	Binary Tree Level Order Traversal	Use breadth-first search or depth-first search.	Medium
32	Clone Graph	Use depth-first search or breadth-first search.	Medium
33	Evaluate Reverse Polish Notation	Use a stack to evaluate the expression.	Medium

Week 4: Medium To Hard

#	Question	Notes	Difficulty
35	Implement Trie (Prefix Tree)	Implement trie data structure.	Medium
36	Coin Change	Use dynamic programming or recursion with memoization.	Medium
37	Product of Array Except Self	Use prefix and suffix products.	Medium
38	Min Stack	Use an additional stack to keep track of minimum element.	Medium
39	Validate Binary Search Tree	Use recursive or iterative inorder traversal.	Medium
40	Number of Islands	Use depth-first search or breadth-first search.	Medium
41	Rotting Oranges	Use breadth-first search.	Medium

Week 5: Half Way

#	Question	Notes	Difficulty
43	Combination Sum	Use backtracking or dynamic programming.	Medium
44	Permutations	Use backtracking to generate permutations.	Medium
45	Merge Intervals	Merge overlapping intervals.	Medium
46	Lowest Common Ancestor of a Binary Tree	Use recursive traversal or parent pointers.	Medium
47	Time-Based Key-Value Store	Implement with a hashmap and binary search.	Medium
48	Accounts Merge	Use union-find or depth-first search.	Medium
49	Sort Colors	Use Dutch National Flag algorithm.	Medium

Week 6: Medium

#	Question	Notes	Difficulty
51	Partition Equal Subset Sum	Use dynamic programming or backtracking with memoization.	Medium
52	String to Integer (atoi)	Handle edge cases and convert string to integer.	Medium
53	Spiral Matrix	Simulate spiral traversal.	Medium
54	Subsets	Generate all possible subsets using backtracking.	Medium
55	Binary Tree Right Side View	Use depth-first search or breadth-first search.	Medium
56	Longest Palindromic Substring	Use dynamic programming or expand around center approach.	Medium
57	Unique Paths	Use dynamic programming to calculate unique paths.	Medium
58	Construct Binary Tree from Preorder and Inorder Traversal	Build tree recursively from preorder and inorder traversal.	Medium

Week 7: Medium

#	Question	Notes	Difficulty
60	Letter Combinations of a Phone Number	Generate letter combinations using backtracking.	Medium
61	Word Search	Use depth-first search with backtracking.	Medium
62	Find All Anagrams in a String	Use sliding window with hashmap.	Medium
63	Minimum Height Trees	Find the center of the graph using iterative removal.	Medium
64	Task Scheduler	Schedule tasks to minimize idle time.	Medium
65	LRU Cache	Implement a data structure using hashmap and doubly linked list.	Medium

Week 7: Hard

#	Question	Notes	Difficulty
67	Minimum Window Substring	Use sliding window with hashmap.	Hard
68	Serialize and Deserialize Binary Tree	Implement using preorder traversal.	Hard
69	Trapping Rain Water	Use two pointers or stack.	Hard
70	Find Median from Data Stream	Use two heaps or balanced binary search tree.	Hard
71	Word Ladder	Use breadth-first search with backtracking.	Hard
72	Basic Calculator	Use stack to evaluate expressions.	Hard
73	Maximum Profit in Job Scheduling	Use dynamic programming with binary search.	Hard
74	Merge k Sorted Lists	Use heap or divide and conquer approach.	Hard
75	Largest Rectangle in Histogram	Use stack to find the maximum area.	Hard