feat: add 001

Author: Blankj

README.md

@@ -20,5 +20,5 @@
 
 
 
-[001]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/001.md
-[007]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/007.md
+[001]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/001/README.md
+[007]: https://github.com/Blankj/awesome-java-leetcode/blob/master/note/007/README.md

note/001/001.md renamed to note/001/README.md

@@ -0,0 +1,30 @@
+# Reverse Integer
+
+## Description
+
+Reverse digits of an integer.
+
+Example1: x = 123, return 321
+Example2: x = -123, return -321
+
+click to show spoilers.
+
+Have you thought about this?
+Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!
+
+If the integer's last digit is 0, what should the output be? ie, cases such as 10, 100.
+
+Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?
+
+For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
+
+Note:
+The input is assumed to be a 32-bit signed integer. Your function should return 0 when the reversed integer overflows.
+
+
+## 思路
+
+
+``` java
+
+```