Topological Sort LeetCode Problems: All 32, With Python Solutions
Every problem in this library that LeetCode tags Topological Sort — 32 in total, 24 of them with a complete Python solution, a worked example and the time and space complexity of the approach.
- 32 problems
- 0 Easy
- 14 Medium
- 18 Hard
How Topological Sort problems are solved
A tag names the subject, not the method. These pattern hubs cover the techniques that actually solve Topological Sort problems — each one explains the approach, gives a Python template and states its complexity.
- Topological Sort — Order a set of tasks so that every dependency comes before the thing that needs it.
Topological Sort problems by difficulty
Problems with a complete Python solution are listed first, then by ascending problem number.
Medium (14)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 207 | Course Schedule | Medium | Depth-First Search, Breadth-First Search, Graph +1 |
| 210 | Course Schedule II | Medium | Depth-First Search, Breadth-First Search, Graph +1 |
| 310 | Minimum Height Trees | Medium | Depth-First Search, Breadth-First Search, Graph +1 |
| 802 | Find Eventual Safe States | Medium | Depth-First Search, Breadth-First Search, Graph +1 |
| 851 | Loud and Rich | Medium | Depth-First Search, Graph, Topological Sort +1 |
| 1462 | Course Schedule IV | Medium | Depth-First Search, Breadth-First Search, Graph +1 |
| 1786 | Number of Restricted Paths From First to Last Node | Medium | Graph, Topological Sort, Dynamic Programming +2 |
| 1976 | Number of Ways to Arrive at Destination | Medium | Graph, Topological Sort, Dynamic Programming +1 |
| 2115 | Find All Possible Recipes from Given Supplies | Medium | Graph, Topological Sort, Array +2 |
| 2192 | All Ancestors of a Node in a Directed Acyclic Graph | Medium | Depth-First Search, Breadth-First Search, Graph +1 |
| 444 | Sequence ReconstructionPremium | Medium | Graph, Topological Sort, Array |
| 1059 | All Paths from Source Lead to DestinationPremium | Medium | Graph, Topological Sort |
| 1136 | Parallel CoursesPremium | Medium | Graph, Topological Sort |
| 1245 | Tree DiameterPremium | Medium | Tree, Depth-First Search, Breadth-First Search +2 |
Hard (18)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 329 | Longest Increasing Path in a Matrix | Hard | Depth-First Search, Breadth-First Search, Graph +5 |
| 913 | Cat and Mouse | Hard | Graph, Topological Sort, Memoization +3 |
| 1203 | Sort Items by Groups Respecting Dependencies | Hard | Depth-First Search, Breadth-First Search, Graph +1 |
| 1632 | Rank Transform of a Matrix | Hard | Union Find, Graph, Topological Sort +3 |
| 1728 | Cat and Mouse II | Hard | Graph, Topological Sort, Memoization +5 |
| 1857 | Largest Color Value in a Directed Graph | Hard | Graph, Topological Sort, Memoization +3 |
| 1916 | Count Ways to Build Rooms in an Ant Colony | Hard | Tree, Graph, Topological Sort +3 |
| 2050 | Parallel Courses III | Hard | Graph, Topological Sort, Array +1 |
| 2127 | Maximum Employees to Be Invited to a Meeting | Hard | Depth-First Search, Graph, Topological Sort |
| 2246 | Longest Path With Different Adjacent Characters | Hard | Tree, Depth-First Search, Graph +3 |
| 2328 | Number of Increasing Paths in a Grid | Hard | Depth-First Search, Breadth-First Search, Graph +5 |
| 2360 | Longest Cycle in a Graph | Hard | Depth-First Search, Breadth-First Search, Graph +1 |
| 2392 | Build a Matrix With Conditions | Hard | Graph, Topological Sort, Array +1 |
| 2603 | Collect Coins in a Tree | Hard | Tree, Graph, Topological Sort +1 |
| 269 | Alien DictionaryPremium | Hard | Depth-First Search, Breadth-First Search, Graph +3 |
| 631 | Design Excel Sum FormulaPremium | Hard | Graph, Design, Topological Sort +4 |
| 1591 | Strange Printer II | Hard | Graph, Topological Sort, Array +1 |
| 2371 | Minimize Maximum Value in a GridPremium | Hard | Union Find, Graph, Topological Sort +3 |
Keep exploring
All LeetCode topicsEvery tag with a page of its own, with the number of problems behind each.LeetCode patternsThe techniques themselves, with a Python template and complexity for each.Curated study listsBlind 75, NeetCode 150 and three more, grouped by pattern.Easy problemsStart here when the data structure is new rather than the problem.
Other topics
- Array1,569
- String672
- Hash Table588
- Math485
- Dynamic Programming481
- Sorting392
- Greedy346
- Depth-First Search289
- Binary Search253
- Database249
- Tree225
- Breadth-First Search223
- Matrix216
- Two Pointers201
- Bit Manipulation194
- Binary Tree174
- Heap (Priority Queue)163
- Prefix Sum157
- Stack157
- Simulation144
- Graph138
- Counting126
- Design122
- Sliding Window116
When the Topological Sort problem arrives live
Stealth Interview is a desktop app for macOS and Windows. It reads the coding problem off your screen, returns a working solution with a step-by-step explanation and its time and space complexity, and transcribes what the interviewer is saying — while staying invisible to screen sharing.