Summary of the questions that I have done
Grind 75
| Question | Difficulty | Date | Remarks | Do again |
|---|---|---|---|---|
| Two Sum | Easy | 11/1 | ||
| Valid Parentheses | Easy | 11/1 | ||
| Merge Two Sorted Lists | Easy | 11/1 | Took a surprising amount of time to do it. I am quite rusty when it comes to thinking logically and thereās lotās of room to improve. | yes |
| Best Time to Buy and Sell Stock | Easy | 12/1 | ||
| Valid Palindrome | Easy | 12/1 | ||
| Binary Search | Easy | 12/1 | ||
| Flood Fill | Easy | 12/1 | ||
| Lowest Common Ancestor of a Binary Search Tree | Medium | 12/1 | ||
| Balanced Binary Tree | Easy | 13/1 | Watched youtube for solution, try again sometime in the future - even though the problem seems simple, i donāt think it is that easy to get to the solution. | yes |
| Linked List Cycle | Easy | 13/1 | ||
| Implement Queue using Stacks | Easy | 13/1 | ||
| First Bad Version | Easy | 13/1 | ||
| Ransom Note | Easy | 13/1 | ||
| Climbing Stairs | Easy | 13/1 | ||
| Longest Palindrome | Easy | 14/1 | ||
| Reverse Linked List | Easy | 14/1 | ||
| Majority Element | Easy | 14/1 | ||
| Add Binary | Easy | 14/1 | Watched neetcode for explanation. V interesting - practice again soon | yes |
| Diameter of Binary Tree | Easy | 14/1 | Did not manage to finish ā feels very similar to Balanced Binary Tree. Will try again tomorrow when my brain is less fogged up. Update 15/1: Managed to complete it without looking at solution! | yes |
| Middle of the Linked List | Easy | 15/1 | ||
| Maximum Depth of Binary Tree | Easy | 15/1 | ||
| Contains Duplicate | Easy | 15/1 | ||
| Maximum Subarray | Medium | 15/1 | ||
| Insert Interval | Medium | 15/1 | Can further optimise with Binary Search | |
| 01 Matrix | Medium | 16/1 | Did a BFS solution by myself, however I couldnāt optimise the solution and it failed runtime complexity. Watched a video and got the inspo to do BFS (in a completely new manner? ) | yes |
| K Closest Points to Origin | Medium | 16/1 | I had the idea but lacked enough knowledge about the heap data structure / how to use in python. Could optimise my solution using heap! Question is actually very doable imo | yes |
| Longest Substring Without Repeating Characters | Medium | 18/1 | ||
| 3Sum | Medium | 18/1 | ||
| Binary Tree Level Order Traversal | Medium | 18/1 | ||
| Clone Graph | Medium | 18/1 | Could not get the solution myself, had to watch the first 3 minutes of leetcode before I realised that I could use a hashmap. My DFS solution is more or less the same but itās not very neat. | yes |
| Evaluate Reverse Polish Notation | Medium | 19/1 | ||
| Course Schedule | Medium | 19/1 | DFS on adjacency matrix. Could code out solution myself after watching neetcode but I feel that the solution I had was not as clean / maybe the idea in my head is not as clear. | yes |
| Implement Trie (Prefix Tree) | Medium | 20/1 | First time doing this question, was actually a lot easier to do once you understand the concepts. | yes |
| Coin Change | Medium | 20/1 | Do again next time! not the first time doing this question but I had to rely on neetcode | yes |
| Product of Array Except Self | Medium | 20/1 | ||
| Min Stack | Medium | 21/1 | ||
| Validate Binary Search Tree | Medium | 21/1 | ||
| Number of Islands | Medium | 21/1 | ||
| Rotting Oranges | Medium | 21/1 | Quite cool, initially thought there was no way I would be able to do this question by myself and wanted to watch neetcode immediately. I gave myself the time to think about it and I managed to come up with the solution! | |
| Search in Rotated Sorted Array | Medium | 22/1 | Managed to come up with the solution myself even though i failed yesterday | |
| Combination Sum | Medium | 22/1 | Done this question before, watched neetcode before coming up with the solution. Still not too confident of the solution (feels that I am memorising the solution) | Yes |
| Permutations | Medium | 23/1 | ||
| Merge Intervals | Medium | 23/1 | ||
| Lowest Common Ancestor of a Binary Tree | Medium | 23/1 | Manage to come up with solution myself (basically a whole if else recursion shit). Watched youtube and realised that there is a more elegant solution with less base cases! | Yes |
| Time Based Key-Value Store | Medium | 26/01 | Came up with a solution myself, a (slightly more optimal) solution that uses binary search exist. I sort of knew it was binary search but I didnāt have the balls to code it up. Should just be brave and practice binary search next time | |
| Accounts Merge | Medium | 27/01 | Alot more complicated than I thought it was. Had to learn about union find Union Find DS. Solution is definitely not trivial but quite fun to do! I think I more or less spent one whole hour (26 & 27 learning about the solution to this problem) | YES |
| Sort Colors | Medium | 27/01 | Did this question before in the past. Happy to be able to do it again by myself this time. | |
| Word Break | Medium | 28/01 | Watched leetcode for inspiration :) | |
| Partition Equal Subset Sum | Medium | 30/01 | Couldnāt do this question on 28/01 but I was actually quite close to the solution. Brain fog is real. | Yes |
| String to Integer (atoi) | Medium | 30/01 | ||
| Spiral Matrix | Medium | 30/01 | Took 2 wrong runs before I found the solution :) |