The BFS solution provided seems unnecessarily complicated, this is what I have in Python that has a space complexity of O(min(m, n)) rather than the O(m * n) described in the solution...

from collections import deque

class Solution:
  def maxAreaOfIsland(self, matrix):
    biggestIslandArea = 0
    rows = len(matrix)
    cols = len(matrix[0])
    for i in range(rows):
      for j in range(cols):
        if matrix[i][j] == 1:
          biggestIslandArea = max(biggestIslandArea, self.visit_land_bfs(matrix, i, j))
    return biggestIslandArea

  def visit_land_bfs(self, matrix, x, y):
    neighbors = deque([(x, y)])
    area = 0

    while neighbors:
      x, y = neighbors.popleft()

      if x < 0 or x >= len(matrix) or y < 0 or y >= len(matrix[0]):
        continue
      if matrix[x][y] == 0:
        continue
      
      matrix[x][y] = 0
      area += 1

      neighbors.append((x + 1, y))
      neighbors.append((x - 1, y))
      neighbors.append((x, y + 1))
      neighbors.append((x, y - 1))

    return area