Module 4Interview Patterns LabLesson 21 of 2315 min
Structure Cheat Sheet
Which structure for which problem — memorize this table.
Pick the right tool
| Problem need | Structure |
|---|
| -------------- | ----------- |
|---|
| Dynamic list / two pointers | Vec / slice |
|---|
| Fast key → value | HashMap |
|---|
| Unique / visited | HashSet |
|---|
| Sorted unique / min-max keys | BTreeSet / BTreeMap |
|---|
| LIFO | Vec stack |
|---|
| FIFO / BFS | VecDeque |
|---|
| Both ends / sliding window | VecDeque |
|---|
| Repeated best element | BinaryHeap |
|---|
| Top-k / min-heap | BinaryHeap<Reverse<_>> |
|---|
| Custom order | sort_by / sort_by_key |
|---|
Always clarify
Constraints (n size), duplicates, sorted input, online vs offline.
Challenge
Add 3 more rows for your weakest topics.
Tips
- Map problem → structure
- State complexity
- Practice under time
Try it live
Structure Cheat SheetRust 2021
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Output
Press Run to compile and execute.