new_contents: class Solution(object):
      def minDistance(self, word1, word2):
          """
          :type word1: str
          :type word2: str
          :rtype: int
          """
          prev = [0] * (len(word2) + 1)
          for i, c1 in enumerate(word1, 1):
              nxt = [0] * (len(word2) + 1)
              for j, c2 in enumerate(word2, 1):
                  if c1 == c2:
                      nxt[j] = prev[j - 1] + 1
                  else:
                      nxt[j] = max(nxt[j - 1], prev[j])
              prev = nxt
          return len(word2) + len(word1) - 2 * prev[len(word2)]
  
subject: Add py solution for 583. Delete Operation for Two Strings