Describe a scenario in which you were required to refactor an existing service. What were the challenges you faced and how did you approach them?

LeetCode #1034 - Color A Border You are given a 2D grid of integers, where each integer represents the color of the cell. You need to color the border of a connected component of the grid with a new color. A border is defined as a cell that is part of the component but is adjacent to at least one cell that is not part of the component. Please implement a function that achieves this. ### Input/Output Input: - grid: List[List[int]] (the grid of colors) - row: int (starting row) - col: int (starting column) - color: int (new color) Output: - List[List[int]] (the modified grid) ### Constraints 1 <= grid.length, grid[0].length <= 50 0 <= grid[i][j] <= 100 0 <= row < grid.length 0 <= col < grid[0].length 0 <= color <= 100 ### Example Input: [[1,1,1],[1,1,0],[1,0,1]] 1 1 2 Output: [[2,2,2],[2,2,0],[2,0,1]]

How do you ensure that an API you design is scalable, secure, and easy to use? What design principles do you follow?