The question is similar to minesweeper https://leetcode.com/problems/minesweeper/
You will get input location of all mines and their blast radius. There will be a chain reaction when a bomb explodes and it would trigger other bombs in it's vicinity. Given this, you need to return how the matrix looks like after some t seconds. Consider this as you're playing the minesweeper game and land on a mine.
Input:
B M2 B B B
B B B B B
B M1 B B M1
B B B B B
Where B is empty space, M[n] is the mine with the blast radius n.
Output:
B X B B B
B B B B B
B X B B M1
B B B B B
After 1 second or first processing where t=1.
I tried using BFS.
I was asked this question in both Amazon and FB, but couldn't find online.