python-data-structures-and-algorithms/src/data_structures/arrays/2D_array.py at master · joaomh/python-data-structures-and-algorithms · GitHub

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"""
Given a 6x6 2D Array, arr:
1 1 1 0 0 0
0 1 0 0 0 0
1 1 1 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0 0 0 0

We define an hourglass 'A' in to be a subset of values with indices
falling in this pattern in 'arr' graphical representation:
a b c
  d
e f g

Function Description
It should return an integer, the maximum hourglass sum in the array.
arr: an array of integers

Input Format
Each of the 6 lines of inputs 'arr' contains 6 space-separated integers arr[i][j].

Constraints
-9 <= arr[i][j] <= 9
0 <= i,j <= 5

Output Format
Print the largest (maximum) hourglass sum found in 'arr'.

Sample Input
1 1 1 0 0 0
0 1 0 0 0 0
1 1 1 0 0 0
0 0 2 4 4 0
0 0 0 2 0 0
0 0 1 2 4 0

Sample Output
19
"""
def hourglass_sum(arr):
  rows = len(arr)
  columns = len(arr[0])
  max_total = True
  for i in range(0, rows-2):
    for j in range(0, columns-2):
        total = arr[i][j] + arr[i][j+1] + arr[i][j+2] + arr[i+1][j+1] \
          + arr[i+2][j] + arr[i+2][j+1] + arr[i+2][j+2]
        if max_total == True:
            max_total = total
        max_total = max(max_total, total)
  return max_total

arr = [[1, 1, 1, 0, 0, 0],
      [0, 1, 0, 0, 0, 0],
      [1, 1, 1, 0, 0, 0],
      [0, 0, 2, 4, 4, 0],
      [0, 0, 0, 2, 0, 0],
      [0, 0, 1, 2, 4, 0],
                        ]
print(hourglass_sum(arr))