Problem Solving

LeetCode

1. Two Sum (Easy)
2. Valid Parentheses (Easy)
3. Reverse Linked List - Recursive and Iterative (Easy)
4. Merge Two Sorted Lists - Recursive and Iterative (Easy)
5. Remove Vowels (Easy)
6. Defanging IP Address (Easy)
7. Roman to Integer (Easy)
8. Implement StrStr (Easy)
9. Symmetric Tree (Easy)
10. Most Common Word (Easy)
11. Reorder Log Files (Easy)
12. Kth Largest Element in Array (Easy)
13. Best Time to Buy and Sell Stocks (Easy)
14. Top K Frequent Mentioned Keywords (Easy)
15. Missing Number (Easy)
16. First Unique Character in a String (Easy)
17. Diameter of Binary Tree (Easy)
18. Flood Fill (Easy)
19. Maximum Subarray (Easy)
20. Min Stack (Easy)
21. Num Islands (Medium)
22. LRU Cache (Medium)
23. Three Sum (Medium)
24. Three Sum Closest (Medium)
25. Longest Substring without Repeating Characters (Medium)
26. String to Integer (atoi) (Medium)
27. Container with Most Water (Medium)
28. Integer to Roman (Medium)
29. Validate BST (Medium)
30. Binary Tree Level Order Traversal (Medium)
31. Binary Tree Zig-Zag Level Order Traversal (Medium)
32. Word Ladder (Medium)
33. Copy List with Random Pointer (Medium)
34. K Closest Points to Origin (Medium)
35. Longest Palindromic Substring (Medium)
36. Rotten Oranges (Medium)
37. Search Suggestions System (Medium)
38. Partition Labels (Medium)
39. Group Anagrams (Medium)
40. Compare Version Numbers (Medium)
41. Product of Array Except Self (Medium)
42. Add Two Numbers (Medium)
43. Course Schedule (Medium)
44. Lowest Common Ancestor of a Binary Tree (Medium)
45. Merge Intervals (Medium)
46. Rotate Image (Medium)
47. Letter Combinations in a Phone Number (Medium)
48. Generate Parentheses (Medium)
49. Unique Path (Medium)
50. Word Search (Medium)
51. Find Index (Medium)
52. Road Trip (Medium)
53. Trapping Rain Water (Hard)
54. Binary Tree Max Path Sum (Hard)
55. Word Ladder II (Hard)
56. Critical Connections in a Network (Hard)
57. Minimum Window Substring (Hard)
58. Merge K Sorted Lists (Hard)
59. Reverse Nodes in k-Group (Hard)
60. Cut Off Trees for Golf Event (Hard)
61. Integer to English Words (Hard)
62. Word Search II (Hard)
63. Median Two Sorted Arrays (Hard)
64. Median From Data Stream (Hard)
65. Electoral Colleges (Hard)

AlgoExpert.io

1. Two Sum (Easy)
2. Find Closest Value in BST (Easy)
3. Branch Sums (Easy)
4. Three Sum (Medium)
5. Smallest Difference (Medium)
6. Move Element to End (Medium)
7. Validate BST (Medium)
8. Pattern Matcher (Hard)
9. Group Anagrams (Medium)
10. Youngest Common Ancestor (Medium)
11. Subarray Sort (Hard)
12. Longest Substring without Duplicates (Hard)
13. Merge Linked Lists (Hard)
14. Binary Tree Max Path Sum (Hard)
15. Lowest Common Manager (Hard)

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Prior to 2020

Interview Bit

Arrays:

• Max Sum Contiguous Subarray (return sum) (Set 2) [Python]
• Spiral Order Matrix II (Set 2) [Python]
• Anti-Diagonals (Set 1) [Python]
• Next Permutation [Python]
• Rain-water Trapped [Python]
• Max Sum Contiguous Subarray (return subarray) [Python]

Math:

• Trailing Zeroes in Factorial (Set 2) [Python]
• FizzBuzz (Set 1) [Python]
• Grid Unique Paths [Python]
• Prime Sum (Set 3) [Python]

Binary Search:

• Square Root of Integer (Set 3) [Python]
• Search Range [Python]
• Rotated Sorted Array Search (Set 2) [Python]
• Median of Two Sorted Arrays (Set 1) [Python]

Strings:

• Reverse the String (Set 1) [Python]
• Unique String [Java]
• Longest Palindromic Substring [Java]

Linked List:

• Remove Duplicates (Set 1) [Java]
• Remove Duplicates Completely (Set 2) [Java]
• Partition List [Python]
• Reverse In-Between Linked List [Python]
• Merge Two Sorted Lists [Python]

Bit Manipulation :

• Divide Integers (Set 3) [Java]

Trees:

• PreOrder Array to Binary Search Tree [Python]

Dynamic Programming:

• Longest Increasing Subsequence [Java]
• Length of Longest Subsequence [Python]
• Edit Distance (Set 3) [Java]
• Longest Palindromic Substring (Set 3) [Java]
• Coin Sum Infinite [Java]
• Max Product Subarray [Java]

Greedy Algorithms:

• Distribute Candy [Java]

Heaps:

• MinIntHeap [Java]

Sorting:

• Counting Sort [Java]
• Simple Bitwise Sort [Java]

LeetCode

• FindX [Java] (Hard - Memoization)

HackerRank

Implementation:

• Grading Students
• Apples And Oranges

WarmUp:

• Simple Array Sum
• Solve Me First
• Compare The Triplets
• A Very Big Sum
• Diagonal Difference