class Solution:
    def floodFill(self, image: List[List[int]], sr: int, sc: int, color: int) -> List[List[int]]:

        newColor = color
        prevColor = image[sr][sc]

        def fill(r, c):
            if r < 0 or c < 0 or r > len(image) - 1 or c > len(image[0]) - 1:
                return

            # check if already visited
            if image[r][c] == newColor:
                return

            # check if the cell is cock-blocked:
            if image[r][c] == prevColor:
                image[r][c] = newColor
            else:
                return

            fill(r - 1, c)
            fill(r, c - 1)
            fill(r + 1, c)
            fill(r, c + 1)

        fill(sr, sc)

        return image