diff --git "a/5. \346\234\200\351\225\277\345\233\236\346\226\207\345\255\220\344\270\262/Document.md" "b/5. \346\234\200\351\225\277\345\233\236\346\226\207\345\255\220\344\270\262/Document.md"
new file mode 100644
index 0000000..c52d719
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+++ "b/5. \346\234\200\351\225\277\345\233\236\346\226\207\345\255\220\344\270\262/Document.md"	
@@ -0,0 +1,15 @@
+## 题目
+给定一个字符串 s，找到 s 中最长的回文子串。你可以假设 s 的最大长度为 1000。
+**Example1:**
+```
+输入: "babad"
+输出: "bab"
+注意: "aba" 也是一个有效答案。
+```
+
+**Example2:**
+```
+输入: "cbbd"
+输出: "bb"
+```
+
diff --git "a/5. \346\234\200\351\225\277\345\233\236\346\226\207\345\255\220\344\270\262/code.py" "b/5. \346\234\200\351\225\277\345\233\236\346\226\207\345\255\220\344\270\262/code.py"
new file mode 100644
index 0000000..721a4dc
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+++ "b/5. \346\234\200\351\225\277\345\233\236\346\226\207\345\255\220\344\270\262/code.py"	
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+# class Solution:
+#     def longestPalindrome(self, s: str) -> str:
+#         maxstr = ''
+#         flag = 0
+#         for i in range(len(s), 0, -1):
+#             if flag == 1:
+#                 break
+#             for j in range(0, len(s)-i+1):
+#                 substr = s[j: j+i]
+#                 if substr == substr[::-1]:
+#                     flag = 1
+#                     maxstr = substr
+#         return maxstr
+
+class Solution:
+    def longestPalindrome(self, s: str) -> str:
+        flag = 0
+        maxstr = ''
+        for i in range(len(s), 0, -1):
+            if flag == 1:
+                break
+            for j in range(0, len(s)-i+1):
+                substr = s[j: j+i]
+                if substr[0: i//2] == substr[i-i//2:][::-1]:
+                    flag = 1
+                    maxstr = substr
+        return maxstr
+
+
+if __name__ == "__main__":
+    solution = Solution()
+    string = 'babad'
+    result = solution.longestPalindrome(string)
+
+    print(result)