message: Update match-substring-after-replacement.py
diff: -# Time: O(n * s)
  -# Space: O(m)
  +# Time: O(n * k), n = len(s), k = len(sub)
  +# Space: O(m), m = len(mappings)
  import collections
  @@ -27,8 +27,8 @@ class Solution(object):
  return any(check(i) for i in xrange(len(s)-len(sub)+1))
  -# Time: O(n * s)
  -# Space: O(m)
  +# Time: O(n * k), n = len(s), k = len(sub)
  +# Space: O(m), m = len(mappings)
  import collections
  