Count Square Submatrices with All Ones in Python

Problem:

Given a m * n matrix of ones and zeros, return how many square submatrices have all ones.

Example 1:

Input: matrix =
[
  [0,1,1,1],
  [1,1,1,1],
  [0,1,1,1]
]

Output: 15

Explanation:
There are 10 squares of side 1.
There are 4 squares of side 2.
There is  1 square of side 3.
Total number of squares = 10 + 4 + 1 = 15.

Example 2:

Input: matrix =
[
  [1,0,1],
  [1,1,0],
  [1,1,0]
]

Output: 7

Explanation:
There are 6 squares of side 1.
There is 1 square of side 2.
Total number of squares = 6 + 1 = 7.

Constraints:

1 <= arr.length <= 300

1 <= arr[0].length <= 300

0 <= arr[i][j] <= 1

Solution:

class Solution:
    def countSquares(matrix):
        p_arr = [[0 for i in range(len(matrix[0]))] for j in range(len(matrix))]
        result = 0

        for index_i in range(1, len(matrix)):
            for index_j in range(1, len(matrix[0])):
                if matrix[index_i][index_j] == 1:
                    temp_mdata = matrix[index_i-1][index_j], matrix[index_i][index_j-1]
                    matrix[index_i][index_j] = min(matrix[index_i-1][index_j-1], min(temp_mdata))+1

        return sum([ sum(x) for x in matrix])


input = [[0,1,1,1],[1,1,1,1],[0,1,1,1]]
print(Solution.countSquares(input))

input = [[1,0,1],[1,1,0],[1,1,0]]
print(Solution.countSquares(input))