添加0028.实现strStr python版本暴力解法

problems/0028.实现strStr.md

@@ -685,7 +685,21 @@ class Solution {
 ```
 
 Python3：
-
+```python
+//暴力解法：
+class Solution(object):
+    def strStr(self, haystack, needle):
+        """
+        :type haystack: str
+        :type needle: str
+        :rtype: int
+        """
+        m,n=len(haystack),len(needle)
+        for i in range(m):
+            if haystack[i:i+n]==needle:
+                return i
+        return -1    
+```	
 ```python
 // 方法一
 class Solution: