import numpy as np

from scipy.sparse.csgraph import breadth_first_order

from scipy.sparse import csr_matrix

​

arr = np.array([

  [0, 1, 0, 1],

  [1, 1, 1, 1],

  [2, 1, 1, 0],

  [0, 1, 0, 1]

])

​

newarr = csr_matrix(arr)

​

print(breadth_first_order(newarr, 1))