Browse problems by topic and difficulty. 3,930 problems indexed.
| Title | Difficulty | ||
|---|---|---|---|
| Design a Number Container System | Medium | Solve |
| Lowest Common Ancestor of a Binary Search Tree | Medium | Solve |
| Shortest Impossible Sequence of Rolls | Hard | Solve |
| First Letter to Appear Twice | Easy | Solve |
| Equal Row and Column Pairs | Medium | Solve |
| Design a Food Rating System | Medium | Solve |
| Number of Excellent Pairs | Hard | Solve |
| Maximum Number of Books You Can Take | Hard | Solve |
| Number of Unique Subjects Taught by Each Teacher | Easy | Solve |
| Make Array Zero by Subtracting Equal Amounts | Easy | Solve |
| Maximum Number of Groups Entering a Competition | Medium | Solve |
| Find Closest Node to Given Two Nodes | Medium | Solve |
| Lowest Common Ancestor of a Binary Tree | Medium | Solve |
| Longest Cycle in a Graph | Hard | Solve |
| Minimum Costs Using the Train Line | Hard | Solve |
| Generate the Invoice | Hard | Solve |
| Merge Similar Items | Easy | Solve |
| Count Number of Bad Pairs | Medium | Solve |
| Task Scheduler II | Medium | Solve |
| Minimum Replacements to Sort the Array | Hard | Solve |
| Number of Arithmetic Triplets | Easy | Solve |
| Reachable Nodes With Restrictions | Medium | Solve |
| Check if There is a Valid Partition For The Array | Medium | Solve |
| Delete Node in a Linked List | Medium | Solve |
| Longest Ideal Subsequence | Medium | Solve |