Practice
Problems to sharpen your skills before a test or an interview. Try as often as you like: nothing here is seen by employers.
Solved 0 of 62
Your progress is kept in this browser. Clearing its cookies starts you afresh.
| Problem | Area | Kind | Difficulty | Your progress |
|---|---|---|---|---|
| Escalation | Account management | Multiple choice | easy | Not tried |
| Activity lifecycle | Android | Multiple choice | easy | Not tried |
| Two sum | Arrays | Code | easy | Not tried |
| Largest sum of a run | Arrays | Code | medium | Not tried |
| Turn a grid | Arrays | Code | medium | Not tried |
| Add two numbers | Basics | Code | easy | Not tried |
| FizzBuzz | Basics | Code | easy | Not tried |
| Value and reference | C# | Multiple choice | easy | Not tried |
| Least privilege | Cloud | Multiple choice | easy | Not tried |
| Autoscaling | Cloud | Multiple choice | medium | Not tried |
| Totals per team | Data | Code | medium | Not tried |
| Least recently used cache | Design | Code | hard | Not tried |
| Compare versions | DevOps | Code | easy | Not tried |
| Count errors in a log | DevOps | Code | easy | Not tried |
| Docker image vs container | DevOps | Multiple choice | easy | Not tried |
| Blue-green deploy | DevOps | Multiple choice | medium | Not tried |
| Kubernetes probes | DevOps | Multiple choice | medium | Not tried |
| Climbing stairs | Dynamic programming | Code | easy | Not tried |
| Fewest coins | Dynamic programming | Code | medium | Not tried |
| Stateless vs stateful | Flutter | Multiple choice | easy | Not tried |
| git pull | Git | Multiple choice | easy | Not tried |
| Undo a pushed commit | Git | Multiple choice | medium | Not tried |
| Count the islands | Graphs | Code | medium | Not tried |
| Shortest way out | Graphs | Code | medium | Not tried |
| First letter that appears once | Hash maps | Code | easy | Not tried |
| Most common word | Hash maps | Code | easy | Not tried |
| The k most frequent numbers | Heaps | Code | medium | Not tried |
| String comparison | Java | Multiple choice | easy | Not tried |
| HashMap and equals | Java | Multiple choice | medium | Not tried |
| == and === | JavaScript | Multiple choice | easy | Not tried |
| typeof null | JavaScript | Multiple choice | easy | Not tried |
| Event loop order | JavaScript | Multiple choice | medium | Not tried |
| let in loops | JavaScript | Multiple choice | medium | Not tried |
| Eloquent N+1 | Laravel | Multiple choice | easy | Not tried |
| WordPress hooks | PHP | Multiple choice | easy | Not tried |
| MVP | Product | Multiple choice | easy | Not tried |
| Prioritising | Product | Multiple choice | medium | Not tried |
| List comprehension | Python | Multiple choice | easy | Not tried |
| Mutable default | Python | Multiple choice | easy | Not tried |
| is vs == | Python | Multiple choice | medium | Not tried |
| Keys in lists | React | Multiple choice | easy | Not tried |
| State updates | React | Multiple choice | medium | Not tried |
| useEffect dependencies | React | Multiple choice | medium | Not tried |
| WHERE vs HAVING | SQL | Multiple choice | easy | Not tried |
| Index use | SQL | Multiple choice | medium | Not tried |
| LEFT JOIN | SQL | Multiple choice | medium | Not tried |
| Transaction isolation | SQL | Multiple choice | hard | Not tried |
| Find the position | Searching and sorting | Code | easy | Not tried |
| Merge meeting times | Searching and sorting | Code | medium | Not tried |
| Storing passwords | Security | Multiple choice | easy | Not tried |
| SQL injection | Security | Multiple choice | medium | Not tried |
| Balanced brackets | Stacks and queues | Code | easy | Not tried |
| Palindrome check | Strings | Code | easy | Not tried |
| Reverse the words | Strings | Code | easy | Not tried |
| Roman numerals | Strings | Code | easy | Not tried |
| Valid anagram | Strings | Code | easy | Not tried |
| Unit vs integration | Testing | Multiple choice | easy | Not tried |
| Boundary values | Testing | Multiple choice | medium | Not tried |
| Flaky test | Testing | Multiple choice | medium | Not tried |
| HTTP status | Web | Multiple choice | easy | Not tried |
| CORS | Web | Multiple choice | medium | Not tried |
| Main thread | iOS | Multiple choice | easy | Not tried |