Open the puzzle, solve it, then come back for the next repetition.
| Focus | Details |
|---|---|
| Language | Rust |
| Problem | Contains Duplicate |
| Difficulty | Easy |
| Puzzle mode | trace |
| Goal | Follow the changing variables and identify the state that must be true. |
Bugl practice
Start Contains Duplicate practice
Practice Task
- Read the code or evidence panel before answering.
- Submit the answer in the Bugl puzzle UI.
- Use the explanation to name the exact rule or pattern you missed.
Problem brief: Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.