@ -35,81 +35,95 @@ If you're running low on time, [AlgoMonster](https://shareasale.com/r.cfm?b=1873
In week 1, we will warm up by doing a mix of easy and medium questions on arrays and strings. Arrays and strings are the most common types of questions to be found in interviews; gaining familiarity with them will help in building strong fundamentals to better handle tougher questions.
- [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/)
| Question | Difficulty | LeetCode |
| :-- | --- | --- |
| Maximum Product Subarray | Medium | [Link](https://leetcode.com/problems/maximum-product-subarray/) |
| Search in Rotated Sorted Array | Medium | [Link](https://leetcode.com/problems/search-in-rotated-sorted-array/) |
## Week 2 - Data structures
The focus of week 2 is on linked lists, strings and matrix-based questions. The goal is to learn the common routines dealing with linked lists, traversing matrices and sequence analysis (arrays/strings) techniques such as sliding window, linked list traversal and matrix traversal.
- [Reverse a Linked List](https://leetcode.com/problems/reverse-linked-list/)
- [Detect Cycle in a Linked List](https://leetcode.com/problems/linked-list-cycle/)
- [Container With Most Water](https://leetcode.com/problems/container-with-most-water/)
- [Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/)
- [Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement/)
- [Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/)
- [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/)
| Question | Difficulty | LeetCode |
| :-- | --- | --- |
| Reverse a Linked List | Easy | [Link](https://leetcode.com/problems/reverse-linked-list/) |
| Detect Cycle in a Linked List | Easy | [Link](https://leetcode.com/problems/linked-list-cycle/) |
| Container With Most Water | Medium | [Link](https://leetcode.com/problems/container-with-most-water/) |
| Find Minimum in Rotated Sorted Array | Medium | [Link](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/) |
| Longest Repeating Character Replacement | Medium | [Link](https://leetcode.com/problems/longest-repeating-character-replacement/) |
| Longest Substring Without Repeating Characters | Medium | [Link](https://leetcode.com/problems/longest-substring-without-repeating-characters/) |
| Number of Islands | Medium | [Link](https://leetcode.com/problems/number-of-islands/) |
| Remove Nth Node From End Of List | Medium | [Link](https://leetcode.com/problems/remove-nth-node-from-end-of-list/) |
| Palindromic Substrings | Medium | [Link](https://leetcode.com/problems/palindromic-substrings/) |
| Pacific Atlantic Water Flow | Medium | [Link](https://leetcode.com/problems/pacific-atlantic-water-flow/) |
| Minimum Window Substring | Hard | [Link](https://leetcode.com/problems/minimum-window-substring/) |
## Week 3 - Non-linear data structures
The focus of week 3 is on non-linear data structures like trees, graphs and heaps. You should be familiar with the various tree traversal (in-order, pre-order, post-order) algorithms and graph traversal algorithms such as breadth-first search and depth-first search. In my experience, using more advanced graph algorithms (Dijkstra's and Floyd-Warshall) is quite rare and usually not necessary.
- [Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/)
- [Construct Binary Tree from Preorder and Inorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/)
- [Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/)
- [Binary Tree Maximum Path Sum](https://leetcode.com/problems/binary-tree-maximum-path-sum/)
| Question | Difficulty | LeetCode |
| :-- | --- | --- |
| Invert/Flip Binary Tree | Easy | [Link](https://leetcode.com/problems/invert-binary-tree/) |
| Validate Binary Search Tree | Medium | [Link](https://leetcode.com/problems/validate-binary-search-tree/) |
| Non-overlapping Intervals | Medium | [Link](https://leetcode.com/problems/non-overlapping-intervals/) |
| Construct Binary Tree from Preorder and Inorder Traversal | Medium | [Link](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/) |
| Top K Frequent Elements | Medium | [Link](https://leetcode.com/problems/top-k-frequent-elements/) |
| Clone Graph | Medium | [Link](https://leetcode.com/problems/clone-graph/) |
| Course Schedule | Medium | [Link](https://leetcode.com/problems/course-schedule/) |
| Serialize and Deserialize Binary Tree | Hard | [Link](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/) |
| Binary Tree Maximum Path Sum | Hard | [Link](https://leetcode.com/problems/binary-tree-maximum-path-sum/) |
#### Optional
- [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/)
- [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)
- [Encode and Decode Strings (LeetCode Premium)](https://leetcode.com/problems/encode-and-decode-strings/)
| Question | Difficulty | LeetCode |
| :-- | --- | --- |
| Maximum Depth of Binary Tree | Easy | [Link](https://leetcode.com/problems/maximum-depth-of-binary-tree/) |
| Same Tree | Easy | [Link](https://leetcode.com/problems/same-tree/) |
| Binary Tree Level Order Traversal | Medium | [Link](https://leetcode.com/problems/binary-tree-level-order-traversal/) |
| Encode and Decode Strings | Medium | [Link](https://leetcode.com/problems/encode-and-decode-strings/) (Premium) |
## Week 4 - More data structures
Week 4 builds up on knowledge from previous weeks but questions are of increased difficulty. Expect to see such level of questions during interviews. You get more practice on more advanced data structures such as (but not exclusively limited to) heaps and tries which are less common but are still asked.
- [Add and Search Word](https://leetcode.com/problems/add-and-search-word-data-structure-design/)
- [Graph Valid Tree (LeetCode Premium)](https://leetcode.com/problems/graph-valid-tree/)
- [Number of Connected Components in an Undirected Graph (LeetCode Premium)](https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/)
| Meeting Rooms II | Medium | [Link](https://leetcode.com/problems/meeting-rooms-ii/) (Premium) |
| Graph Valid Tree | Medium | [Link](https://leetcode.com/problems/graph-valid-tree/) (Premium) |
| Number of Connected Components in an Undirected Graph | Medium | [Link](https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/) (Premium) |
| Alien Dictionary | Hard | [Link](https://leetcode.com/problems/alien-dictionary/) (Premium) |
## Week 5 - Dynamic programming
@ -119,16 +133,18 @@ DP questions can be hard to master and the best way to get better at them is...
Practically speaking the return of investment (ROI) on studying and practicing for DP questions is very low. Hence DP questions are less important/optional and you should only do them if you have time to spare and you're very keen to have all bases covered (and interviewing with Google).
Yangshun
4 years ago