My LeetCode journey
27 problems solved.
Bookmarked
- 437. Path Sum III
Restudy this problem.
| # | Title | Difficulty | Tags | Solved |
|---|---|---|---|---|
| 104 | Maximum Depth of Binary Tree | Easy | treebinary-treedfs | 2026-10-05 |
| 199 | Binary Tree Right Side View | Medium | treebinary-treebfs | 2026-10-06 |
| 206 | Reverse Linked List | Easy | linked-listrecursion | 2026-10-05 |
| 236 | Lowest Common Ancestor of a Binary Tree | Medium | treebinary-treedfs | 2026-10-06 |
| 328 | Odd Even Linked List | Medium | linked-list | 2026-10-05 |
| 394 | Decode String | Medium | stackstringrecursion | 2026-10-02 |
| 437 | Path Sum III | Medium | treebinary-treedfsprefix-sumhash-table | 2026-10-05 |
| 643 | Maximum Average Subarray I | Easy | sliding-windowarray | 2026-09-24 |
| 649 | Dota2 Senate | Medium | queuegreedystring | 2026-10-05 |
| 724 | Find Pivot Index | Easy | prefix-sumarray | 2026-10-01 |
| 735 | Asteroid Collision | Medium | stackarraysimulation | 2026-10-02 |
| 872 | Leaf-Similar Trees | Easy | treebinary-treedfs | 2026-10-05 |
| 933 | Number of Recent Calls | Easy | queuedesigndata-stream | 2026-10-04 |
| 1004 | Max Consecutive Ones III | Medium | sliding-windowarray | 2026-09-24 |
| 1161 | Maximum Level Sum of a Binary Tree | Medium | treebinary-treebfs | 2026-10-06 |
| 1207 | Unique Number of Occurrences | Easy | hash-tablearray | 2026-10-01 |
| 1372 | Longest ZigZag Path in a Binary Tree | Medium | treebinary-treedfsdynamic-programming | 2026-10-06 |
| 1448 | Count Good Nodes in Binary Tree | Medium | treebinary-treedfs | 2026-10-05 |
| 1456 | Maximum Number of Vowels in a Substring of Given Length | Medium | sliding-windowstring | 2026-09-24 |
| 1493 | Longest Subarray of 1's After Deleting One Element | Medium | sliding-windowarray | 2026-10-01 |
| 1657 | Determine if Two Strings Are Close | Medium | hash-tablestringcounting | 2026-10-01 |
| 1732 | Find the Highest Altitude | Easy | prefix-sumarray | 2026-10-01 |
| 2095 | Delete the Middle Node of a Linked List | Medium | linked-listtwo-pointers | 2026-10-05 |
| 2130 | Maximum Twin Sum of a Linked List | Medium | linked-listtwo-pointers | 2026-10-05 |
| 2215 | Find the Difference of Two Arrays | Easy | hash-tablearray | 2026-10-01 |
| 2352 | Equal Row and Column Pairs | Medium | hash-tablematrixarray | 2026-10-01 |
| 2390 | Removing Stars From a String | Medium | stackstring | 2026-10-01 |
Concepts
Algorithms and techniques that recur across problems.
- Breadth-first search
Visit every node one step from the start, then every node two steps away, and so on outward. A queue keeps the nodes in the order they were found, which makes breadth-first search the tool for fewest-step paths and level-by-level work.
graphtreequeue
- Depth-first search
Follow one path as deep as it goes, then back up to the most recent branch not yet tried. A stack holds the branches still to try, and a visited set keeps cycles from looping forever.
graphtreestackrecursion
Utilities
How language and library features behave.
- How Python's zip pairs lists
zip walks several lists in step, taking the item at the same position from each and yielding them together as a tuple. It stops as soon as the shortest list runs out, so the leftover items of longer lists are never read.
pythoniteration