Minimum Obstacle Removal

Problem Overview

• Given a 2D matrix with '.', '#', and '|', determine the minimum number of obstacles ('#') to remove so all '|' shapes fall to the bottom under gravity.
• Input: matrix of symbols; Output: an integer for the minimum obstacles removed; constraints not specified.
• Represents a grid-based gravity scenario, like falling pieces in games or physical systems.
• Asked in Uber interviews; a coding interview problem often seen as an interview question.