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Practice Rotting Oranges

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Medium#994
LeetCode Problem

Rotting Oranges

ArrayBreadth-First SearchMatrix

Problem Statement

The grid uses 0 for an empty cell, 1 for a fresh orange, and 2 for a rotten orange. In each minute, all currently rotten oranges infect fresh neighbors above, below, left, and right simultaneously. Find how many minutes are required until no fresh oranges remain. Return -1 if any fresh orange is unreachable, or 0 if none are fresh initially. Practice approach: Start breadth-first search with every initially rotten cell in the queue. Process one queue layer per minute while tracking the number of fresh oranges. Mark an orange when enqueuing it so it is not counted twice. Each grid cell is processed at most once: O(m*n) time and space.

Source: Rotting Oranges on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input
grid = [[2,1,1],[1,1,0],[0,1,1]]
Output
4

# Example 2

Input
grid = [[2,1,1],[0,1,1],[1,0,1]]
Output
-1

# Example 3

Input
grid = [[0,2]]
Output
0

Constraints

m == grid.length
n == grid[i].length
1 <= m, n <= 10
grid[i][j] is 0, 1, or 2.

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