#0268

Rotting Oranges

MediumDSA28 min20 XP

Problem

Grid values are 0 empty, 1 fresh orange, and 2 rotten orange. Each minute, rotten oranges rot adjacent fresh oranges. Return minutes until all are rotten, or -1 if impossible.

Why This Matters

This is the cleanest example of BFS starting from many sources at once.

Function Signature

def oranges_rotting(grid):

Examples

Example 1

Inputgrid = [[2,1,1],[1,1,0],[0,1,1]]

Output4

The rot spreads layer by layer and reaches the final orange after 4 minutes.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Use the intended DSA pattern when brute force would scale poorly.

CodePython

def oranges_rotting(grid):
    """
    Input example: grid = [[2,1,1],[1,1,0],[0,1,1]]
    Return: 4
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return 0

def oranges_rotting(grid):
    """
    Input example: grid = [[2,1,1],[1,1,0],[0,1,1]]
    Return: 4
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return 0

Visible browser tests run here when available.

Testcases2 visible / 3 hidden categories

All eventually rot

Input[[2,1,1],[1,1,0],[0,1,1]]

Expected4

Four BFS layers are needed.

Unreachable fresh orange

Input[[2,1,1],[0,1,1],[1,0,1]]

Expected-1

Some fresh oranges are isolated from all rotten sources.

Hidden Test Categories

no fresh orangesno rotten orangesone-cell grid