A curated collection of solutions I have cooked up while tackling problems from Coding Interview platforms. Most of the problems have at least two solutions. But if a problem is too easy, I just keep it simple.
Initially, I jump into each problem with a 💡blank slate, without of any external resources or prior research. Then, after I solve it, I engage in thorough online study, analyzing the best solutions available 🎯, exploring different angles and approaches. Armed with these new ideas, I reconstruct the problems using my own understanding and methodologies.
Let's face it, sometimes That's when I have to |
Each solution I present is accompanied by a detailed explanation, providing insights into its time and space complexities. I'm thrilled to share this project, and hope you'll find them as enlightening and enjoyable as I do while working on it.
two-number-sumvalidate-subsequencewater-area
| Problem Statement | Hurdle | Category | Solutions | Paper |
|---|---|---|---|---|
| Two Number Sum | 🟩 | Arrays |   |
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| Validate Subsequence | 🟩 | Arrays | |
|
| Tournament Winner | 🟩 | Arrays | ||
| Non-Constructible Change | 🟩 | Arrays | ||
| Sorted Squared Array | 🟩 | Arrays | ||
| Three Number Sum | 🟦 | Arrays | ||
| Smallest Difference | 🟦 | Arrays | ||
| Move Element To End | 🟦 | Arrays | ||
| Monotonic Array | 🟦 | Arrays | ||
| Spiral Traverse | 🟦 | Arrays | ||
| Longest Peak | 🟦 | Arrays | ||
| Array Of Products | 🟦 | Arrays | ||
| First Duplicate Value | 🟦 | Arrays | ||
| Merge Overlapping Intervals | 🟦 | Arrays | ||
| Four Number Sum | 🟥 | Arrays | ||
| Subarray Sort | 🟥 | Arrays | ||
| Largest Range | 🟥 | Arrays | ||
| Min Rewards | 🟥 | Arrays | ||
| Zigzag Traverse | 🟥 | Arrays | ||
| Apartment Hunting | ⬛ | Arrays | ||
| Calendar Matching | ⬛ | Arrays | ||
| Waterfall Streams | ⬛ | Arrays | ||
| Minimum Area Rectangle | ⬛ | Arrays | ||
| Line Through Points | ⬛ | Arrays | ||
| Palindrome Check | 🟩 | Strings | ||
| Caesar Cypher Encryptor | 🟩 | Strings | ||
| Run-Length Encoding | 🟩 | Strings | ||
| Generate Document | 🟩 | Strings | ||
| First Non-Repeating Character | 🟩 | Strings | ||
| Longest Palindromic Substring | 🟦 | Strings | ||
| Group Anagrams | 🟦 | Strings | ||
| Valid IP Addresses | 🟦 | Strings | ||
| Reverse Words In String | 🟦 | Strings | ||
| Minimum Characters For Words | 🟦 | Strings | ||
| Longest Substring Without Duplication | 🟥 | Strings | ||
| Underscorify Substring | 🟥 | Strings | ||
| Pattern Matcher | 🟥 | Strings | ||
| Smallest Substring Containing | ⬛ | Strings | ||
| Longest Balanced Substring | ⬛ | Strings | ||
| Remove Duplicates From Linked List | 🟩 | Linked Lists | ||
| Linked List Construction | 🟦 | Linked Lists | ||
| Remove Kth Node From End | 🟦 | Linked Lists | ||
| Sum of Linked Lists | 🟦 | Linked Lists | ||
| Find Loop | 🟥 | Linked Lists | ||
| Reverse Linked List | 🟥 | Linked Lists | ||
| Merge Linked Lists | 🟥 | Linked Lists | ||
| Shift Linked List | 🟥 | Linked Lists | ||
| LRU Cache | ⬛ | Linked Lists | ||
| Rearrange Linked List | ⬛ | Linked Lists | ||
| Linked List Palindrome | ⬛ | Linked Lists | ||
| Zip Linked List | ⬛ | Linked Lists | ||
| Node Swap | ⬛ | Linked Lists | ||
| Min Max Stack Construction | 🟦 | Stacks | ||
| Balanced Brackets | 🟦 | Stacks | ||
| Sunset Views | 🟦 | Stacks | ||
| Sort Stack | 🟦 | Stacks | ||
| Shorten Path | 🟥 | Stacks | ||
| Largest Rectangle Under Skyline | 🟥 | Stacks | ||
| Binary Search | 🟩 | Searching | ||
| Find Three Largest Numbers | 🟩 | Searching | ||
| Search In Sorted Matrix | 🟦 | Searching | ||
| Shifted Binary Search | 🟥 | Searching | ||
| Search For Range | 🟥 | Searching | ||
| Quickselect | 🟥 | Searching | ||
| Index Equals Value | 🟥 | Searching | ||
| Bubble Sort | 🟩 | Sorting | ||
| Insertion Sort | 🟩 | Sorting | ||
| Selection Sort | 🟩 | Sorting | ||
| Three Number Sort | 🟦 | Sorting | ||
| Quick Sort | 🟥 | Sorting | ||
| Heap Sort | 🟥 | Sorting | ||
| Radix Sort | 🟥 | Sorting | ||
| Merge Sort | ⬛ | Sorting | ||
| Minimum Waiting Time | 🟩 | Greedy Algorithms | ||
| Class Photos | 🟩 | Greedy Algorithms | ||
| Tandem Bicycle | 🟩 | Greedy Algorithms | ||
| Task Assignment | 🟦 | Greedy Algorithms | ||
| Valid Starting City | 🟦 | Greedy Algorithms | ||
| Min Heap Construction | 🟦 | Heaps | ||
| Continuous Median | 🟥 | Heaps | ||
| Sort K-Sorted Array | 🟥 | Heaps | ||
| Laptop Rentals | 🟥 | Heaps | ||
| Merge Sorted Arrays | ⬛ | Heaps | ||
| Kadane's Algorithm | 🟦 | Famous Algorithms | ||
| Dijkstra's Algorithm | 🟥 | Famous Algorithms | ||
| Topological Sort | 🟥 | Famous Algorithms | ||
| Knuth Morris Pratt Algorithm | ⬛ | Famous Algorithms | ||
| A* Algorithm | ⬛ | Famous Algorithms | ||
| Nth Fibonacci | 🟩 | Recursion | ||
| Product Sum | 🟩 | Recursion | ||
| Permutations | 🟦 | Recursion | ||
| Powerset | 🟦 | Recursion | ||
| Phone Number Mnemonics | 🟦 | Recursion | ||
| Staircase Traversal | 🟦 | Recursion | ||
| Lowest Common Manager | 🟥 | Recursion | ||
| Interweaving Strings | 🟥 | Recursion | ||
| Solve Sudoku | 🟥 | Recursion | ||
| Ambiguous Measurements | 🟥 | Recursion | ||
| Generate Div Tags | 🟥 | Recursion | ||
| Number Of Binary Tree Topologies | ⬛ | Recursion | ||
| Non Attacking Queens | ⬛ | Recursion | ||
| Find Closest Value In BST | 🟩 | Binary Search Trees | ||
| BST Traversal | 🟦 | Binary Search Trees | ||
| BST Construction | 🟦 | Binary Search Trees | ||
| Validate BST | 🟦 | Binary Search Trees | ||
| Min Height BST | 🟦 | Binary Search Trees | ||
| Find Kth Largest Value In BST | 🟦 | Binary Search Trees | ||
| Reconstruct BST | 🟦 | Binary Search Trees | ||
| Validate Three Nodes | 🟥 | Binary Search Trees | ||
| Same BSTs | 🟥 | Binary Search Trees | ||
| Right Smaller Than | ⬛ | Binary Search Trees | ||
| Branch Sums | 🟩 | Binary Trees | ||
| Node Depths | 🟩 | Binary Trees | ||
| Invert Binary Tree | 🟦 | Binary Trees | ||
| Binary Tree Diameter | 🟦 | Binary Trees | ||
| Find Successor | 🟦 | Binary Trees | ||
| Height Balanced Binary Tree | 🟦 | Binary Trees | ||
| Max Path Sum In Binary Tree | 🟥 | Binary Trees | ||
| Find Nodes Distance K | 🟥 | Binary Trees | ||
| Iterative In-Order Traversal | ⬛ | Binary Trees | ||
| Flatten Binary Tree | ⬛ | Binary Trees | ||
| Right Sibling Tree | ⬛ | Binary Trees | ||
| All Kinds of Node Depths | ⬛ | Binary Trees | ||
| Compare Leaf Traversal | ⬛ | Binary Trees | ||
| Max Subset Sum No Adjacent | 🟦 | Dynamic Programming | ||
| Number Of Ways To Make Change | 🟦 | Dynamic Programming | ||
| Min Number Of Coins For Change | 🟦 | Dynamic Programming | ||
| Levenshtein Distance | 🟦 | Dynamic Programming | ||
| Number Of Ways To Traverse Graph | 🟦 | Dynamic Programming | ||
| Max Sum Increasing Subsequence | 🟥 | Dynamic Programming | ||
| Longest Common Subsequence | 🟥 | Dynamic Programming | ||
| Min Number of Jumps | 🟥 | Dynamic Programming | ||
| Water Area | 🟥 | Dynamic Programming | |
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| Knapsack Problem | 🟥 | Dynamic Programming | ||
| Disk Stacking | 🟥 | Dynamic Programming | ||
| Numbers In Pi | 🟥 | Dynamic Programming | ||
| Maximum Sum Submatrix | 🟥 | Dynamic Programming | ||
| Maximize Expression | 🟥 | Dynamic Programming | ||
| Max Profit With K Transactions | ⬛ | Dynamic Programming | ||
| Palindrome Partitioning Min Cuts | ⬛ | Dynamic Programming | ||
| Longest Increasing Subsequence | ⬛ | Dynamic Programming | ||
| Longest String Chain | ⬛ | Dynamic Programming | ||
| Square Of Zeroes | ⬛ | Dynamic Programming | ||
| Depth-First Search | 🟩 | Graphs | ||
| Single Cycle Check | 🟦 | Graphs | ||
| Breadth-First Search | 🟦 | Graphs | ||
| River Sizes | 🟦 | Graphs | ||
| Youngest Common Ancestor | 🟦 | Graphs | ||
| Remove Islands | 🟦 | Graphs | ||
| Cycle In Graph | 🟦 | Graphs | ||
| Minimum Passes Of Matrix | 🟦 | Graphs | ||
| Boggle Board | 🟥 | Graphs | ||
| Rectangle Mania | ⬛ | Graphs | ||
| Airport Connections | ⬛ | Graphs | ||
| Detect Arbitrage | ⬛ | Graphs | ||
| Two-Edge Connected Graph | ⬛ | Graphs | ||
| Suffix Trie Construction | 🟦 | Tries | ||
| Multi String Search | 🟥 | Tries |
| Color | Description |
|---|---|
| 🟩 | Easy |
| 🟦 | Medium |
| 🟥 | Hard |
| ⬛ | Very Hard |