Compute time for virus to infect grid

You are given an `m x n` grid representing the state of individuals in a lab. - `0` = empty cell (no one) - `1` = healthy individual - `2` = infected individual Every minute, any **healthy** individual (`1`) that is **4-directionally adjacent** (up/down/left/right) to an infected individual (`2`) becomes infected. Return the **minimum number of minutes** needed until **no healthy individuals remain**. If it is **impossible** to infect all healthy individuals, return `-1`. If there are **no healthy individuals initially**, return `0`. ### Input - A 2D integer array `grid` of size `m x n`. ### Output - An integer: the minimum minutes to infect everyone, or `-1` if impossible. ### Constraints - `1 ≤ m, n ≤ 200` - `grid[i][j] ∈ {0,1,2}` ### Notes (as in the interview) - You may be asked to write your own test cases (including edge cases) to validate your solution.