Compute grid shortest path with obstacles
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: Medium
Interview Round: Technical Screen
You are given an m x n grid of integers where cells with value -1 represent obstacles and all other cells are traversable. Starting at (0,
0) and targeting (m-1, n-
1), compute the length of the shortest path using only four-directional moves (up, down, left, right). Return -1 if the target is unreachable. Describe your algorithm, prove its correctness at a high level, analyze time and space complexities, cover edge cases (e.g., blocked start/goal, single-cell grid), and provide pseudocode.
Quick Answer: This question evaluates understanding of grid-based graph traversal, shortest-path reasoning, and obstacle handling, testing competence in algorithmic problem-solving and complexity analysis within the Coding & Algorithms domain.
