# Java Interview with a FAANG engineer

### Interview Summary

**Problem type**: Shortest Path in Binary Matrix  
**Interview question**: Given an n x n binary matrix grid, return the length of the shortest clear path in the matrix. If there is no clear path, return -1.

A clear path in a binary matrix is a path from the top-left cell (i.e., (0, 0)) to the bottom-right cell (i.e., (n - 1, n - 1)) such that:
- All the visited cells of the path are 0.
- All the adjacent cells of the path are 8-directionally connected (i.e., they share an edge or a corner).
- The length of a clear path is the number of visited cells of this path.

### Example 1.
**Input**: grid = 
```
[[0,0,0],
 [1,1,0],
 [1,1,0]]
```
**Output**: length = 4

### Example 2.
**Input**: grid = 
```
[[0,1,1,1],
 [0,0,1,0],
 [0,1,1,0],
 [1,1,1,0]]
```
**Output**: -1

### Interview Feedback
**Feedback about Effulgent Covariate (the interviewee)**
- Advance this person to the next round? **No**
- How were their technical skills? **3/4**
- How was their problem-solving ability? **3/4**
- What about their communication ability? **4/4**

> Thank you for another productive session.
> We focused on a DSA problem where there were several positive signals and some mixed. 
> Recommendation for next session: After you've completed a majority of 3 or 4 first sections on Neetcode 150, let's focus a DSA round on one of those (could be 'mock' or 'mentorship').

**Strengths:**
- **Communication**
  - Clarifying questions, e.g., getting buy-in for "directions" to explore neighbors.
  - Affable and proactive in proposing next steps.
  - Articulated overall strategy before starting to code.
- **Problem solving**
  - Proposed BFS algorithm early on.
  - Quick adoption of hints.
- **Technical**
  - Comfortable with queues in Java.

**Potential areas of improvement**
- Recommend to verbalize a brute force solution first and state time and space for it.
- Time management: aim for ~4-5 minutes for clarifying questions/setup.
- Technical:
  - Recommend to provide time/space complexity (worst case) near completion of most coding tasks.

### Interview Transcript

**Effulgent Covariate**: Yeah. So mainly my focus has been working my way through the...
**Stochastic Panda**: A bit of both would be great.

#### [Discussion about approaches for problem-solving]

**Effulgent Covariate**: I felt like if I got to the graphing section of the practice, I probably would have done a lot better on this.

**Stochastic Panda**: I stood out that your intuition for finding an algorithm is a lot better and faster.

### Further suggestions
- **Neetcode 150** first ~11 sections: Arrays to Graphs
- Recommend consistency in cadence for DSA: after completing 3 or 4 sections, a DSA round to solidify.