Update 0247._Strobogrammatic_Number_II.md

docs/Leetcode_Solutions/Python/0247._Strobogrammatic_Number_II.md

@@ -45,12 +45,7 @@ Output: ["11","69","88","96"]
 
 ```python
 class Solution:
-    def findStrobogrammatic(self, n):
-        """
-        :type n: int
-        :rtype: List[str]
-        """
-
+    def findStrobogrammatic(self, n: int) -> List[str]:
         def helper(n):
             if n == 0:
                 return ['']
@@ -66,11 +61,11 @@ class Solution:
                 res.append('9' + s + '6')
             return res
 
-        if n == 0:
-            return ['']
-        if n == 1:
-            return ['0', '1', '8']
-        return [s for s in helper(n) if s[0] != '0'] 
+        res = []
+        for s in helper(n):
+            if not (len(s) > 1 and s[0] == '0'):
+                res.append(s)
+        return res 
 ```
 
 > 思路 2
@@ -80,26 +75,23 @@ class Solution:
 
 ```python
 class Solution:
-    def findStrobogrammatic(self, n):
-        """
-        :type n: int
-        :rtype: List[str]
-        """
-        res = [''] if n % 2 == 0 else ['0', '1', '8']
+    def findStrobogrammatic(self, n: int) -> List[str]:
+        stack = [''] if n % 2 == 0 else ['0', '1', '8']
         for i in range(n%2+1, n, 2):
             cur = []
-            for s in res:
+            for s in stack:
                 cur.append('0' + s + '0')
                 cur.append('1' + s + '1')
                 cur.append('6' + s + '9')
                 cur.append('8' + s + '8')
                 cur.append('9' + s + '6')
-            res = cur[:]
-        if n == 0:
-            return ['']
-        if n == 1:
-            return ['0', '1', '8']
-        return [s for s in res if s[0] != '0']
+            stack = cur[:]
+
+        res = []
+        for s in stack:
+            if not (len(s) > 1 and s[0] == '0'):
+                res.append(s)
+        return res
 ```