Update 0271-encode-and-decode-strings.py

Shortened the encode function to a one-liner.
Refactored decode function to cleanly use index variables i and j.

Author: Chris Cooper

python/0271-encode-and-decode-strings.py

@@ -1,28 +1,19 @@
 class Solution:
-    """
-    @param: strs: a list of strings
-    @return: encodes a list of strings to a single string.
-    """
-
     def encode(self, strs):
-        res = ""
-        for s in strs:
-            res += str(len(s)) + "#" + s
-        return res
-
-    """
-    @param: s: A string
-    @return: decodes a single string to a list of strings
-    """
+        return ''.join(map(lambda s: str(len(s)) + '#' + s, strs))
 
     def decode(self, s):
-        res, i = [], 0
-
+        res = []
+        i = 0
+        
         while i < len(s):
             j = i
-            while s[j] != "#":
+            while s[j] != '#':
                 j += 1
             length = int(s[i:j])
-            res.append(s[j + 1 : j + 1 + length])
-            i = j + 1 + length
+            i = j + 1
+            j = i + length
+            res.append(s[i:j])
+            i = j
+            
         return res