Count Connected Components

Problem

Count the connected components of 1-valued pixels in a binary mask using 4-connectivity.

Pixels that touch only diagonally belong to different components. An empty mask has 0 components.

Hint

Scan every pixel; when you hit an unseen 1, flood fill it and increment the count.

case 1

in: [[[1,1,0],[0,1,0],[0,0,1]]]

expected: 2

case 2

in: [[[1,0],[0,1]]]

expected: 2

case 3

in: [[[0,0],[0,0]]]

expected: 0

case 4

in: [[[1,1,1],[1,1,1]]]

expected: 1

case 5

in: [[]]

expected: 0

Starter codePython

def count_components(mask):
    # Your code here
    pass

5 test cases · run your code against them in the editor