Matrix BFS Traversal | Dataford Interview Questions

Matrix traversal using BFS (edge-case heavy).

Asked in the Online technical screening stage.

Implement bfs_matrix(matrix, start_row, start_col). The matrix is rectangular and contains 1 for an open cell and 0 for a blocked cell. Starting at the given coordinate, return reachable open-cell coordinates in BFS order. Explore neighbors in this order: up, right, down, left. Return an empty list for an empty matrix, an invalid start coordinate, or a blocked starting cell.

Input and Output

matrix is a list of binary integer rows. start_row and start_col are integers. Return a list of [row, col] coordinate lists.

Constraints

0 <= len(matrix) <= 10000
The matrix is rectangular when non-empty
Each cell is either 0 or 1
start_row and start_col are integers
The matrix contains at most 10000 cells

Function Signature

def bfs_matrix(matrix, start_row, start_col):

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