Rotting Oranges

You are given an m x n grid where each cell can have one of three values:

• 0 representing an empty cell
• 1 representing a fresh orange
• 2 representing a rotten orange

Every minute, any fresh orange that is 4-directionally adjacent to a rotten orange becomes rotten.

Return the minimum number of minutes that must elapse until no cell has a fresh orange. If this is impossible, return -1.

Examples

Example 1:

Input: grid = [[2,1,1],[1,1,0],[0,1,1]]

Output: 4

Explanation: At minute 0 the top-left orange is rotten. It takes 4 minutes for all fresh oranges to become rotten.

Example 2:

Input: grid = [[2,1,1],[0,1,1],[1,0,1]]

Output: -1

Explanation: The bottom-left orange (row 2, col 0) can never be reached by any rotten orange.

Example 3:

Input: grid = [[0,2]]

Output: 0

Explanation: There are no fresh oranges at minute 0, so the answer is 0.

Constraints

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