添加0093.复原IP地址python3版本，思路清晰

problems/0093.复原IP地址.md

@@ -309,7 +309,34 @@ class Solution {
 ```
 
 python版本：
+```python
+class Solution:
+    def restoreIpAddresses(self, s: str) -> List[str]:
+        res = []
+        path = [] # 存放分割后的字符
+        # 判断数组中的数字是否合法
+        def isValid(p):
+            if p == '0': return True # 解决"0000"
+            if p[0] == '0': return False
+            if int(p) > 0 and int(p) <256: return True
+            return False
         
+        def backtrack(s, startIndex):
+            if len(s) > 12: return  # 字符串长度最大为12
+            if len(path) == 4 and startIndex == len(s): # 确保切割完，且切割后的长度为4
+                res.append(".".join(path[:])) # 字符拼接
+                return 
+
+            for i in range(startIndex, len(s)):
+                p = s[startIndex:i+1] # 分割字符
+                if isValid(p): # 判断字符是否有效
+                    path.append(p)
+                else: continue
+                backtrack(s, i + 1) # 寻找i+1为起始位置的子串
+                path.pop()
+        backtrack(s, 0)
+        return res
+```
 ```python
 class Solution(object):
     def restoreIpAddresses(self, s):