Update README.md

Author: pezy chen

README.md

@@ -6,7 +6,7 @@ LeetCode solutions in C++ 11 and Python3.
 |NO.|Title|Solution|Note|Difficulty|Tag|
 |---|-----|--------|----|----------|---|
 |0|[Two Sum](https://leetcode.com/problems/two-sum)|[C++](000.%20Two%20Sum/solution.h) [Python](000.%20Two%20Sum/solution.py)|[Note](000.%20Two%20Sum)|Easy|`Mapping`|
-|1|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers)|[C++](001.%20Add%20Two%20Numbers/solution.h) [Python](001.%20Add%20Two%20Numbers/solution.py)|[Note](001.%20Add%20Two%20Numbers)|Medium|`Linked List`|
+|1|[Add Two Numbers](https://leetcode.com/problems/add-two-numbers)|[C++](001.%20Add%20Two%20Numbers/solution.h) [Python](001.%20Add%20Two%20Numbers/solution.py)|[Note](001.%20Add%20Two%20Numbers)|Medium|`LinkedList`|
 |2|[Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters)|[C++](002.%20Longest%20Substring%20Without%20Repeating%20Characters/solution.h) [Python](002.%20Longest%20Substring%20Without%20Repeating%20Characters/solution.py)|[Note](002.%20Longest%20Substring%20Without%20Repeating%20Characters)|Medium|`Mapping`|
 |3|[Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays)|[C++](003.%20Median%20of%20Two%20Sorted%20Arrays/solution.h) [Python](003.%20Median%20of%20Two%20Sorted%20Arrays/solution.py)|[Note](003.%20Median%20of%20Two%20Sorted%20Arrays)|Hard|
 |4|[Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring)|[C++](004.%20Longest%20Palindromic%20Substring/solution.h) [Python](004.%20Longest%20Palindromic%20Substring/solution.py)|[Note](004.%20Longest%20Palindromic%20Substring)|Medium|