new_contents: """Leetcode 221. Maximal Square
  Medium
  
  URL: https://leetcode.com/problems/maximal-square/
  
  Given a 2D binary matrix filled with 0's and 1's, find the largest
  square containing only 1's and return its area.
  
  Example:
  Input: 
  1 0 1 0 0
  1 0 1 1 1
  1 1 1 1 1
  1 0 0 1 0
  Output: 4
  """
  
  
  class Solution(object):
      def maximalSquare(self, matrix):
          """
          :type matrix: List[List[str]]
          :rtype: int
          """
          pass
  
  
  def main():
      pass
  
  
  if __name__ == '__main__':
      main()
  
subject: Add lc0221_maximal_square.py