feat: reverse integer

README.md

@@ -14,6 +14,7 @@
 |297|[二叉树的序列化与反序列化](https://leetcode-cn.com/problems/serialize-and-deserialize-binary-tree/)  | [Golang](./content/blog/algorithm/297.md)|
 |99|[恢复二叉搜索树](https://leetcode-cn.com/problems/recover-binary-search-tree/)| [Golang](./content/blog/algorithm/99.md)|
 |35|[搜索插入位置](https://leetcode-cn.com/problems/search-insert-position/)| [Golang](./content/blog/algorithm/35.md)|
+|7|[整数反转](https://leetcode-cn.com/problems/reverse-integer/)| [Golang](./content/blog/algorithm/7.md)|
 |6|[Z 字形变换](https://leetcode-cn.com/problems/zigzag-conversion/submissions/)| [Golang](./content/blog/algorithm/6.md)|
 |5|[最长回文子串](https://leetcode-cn.com/problems/longest-palindromic-substring/)| [Golang](./content/blog/algorithm/5.md)|
 |4|[寻找两个有序数组的中位数](https://leetcode-cn.com/problems/median-of-two-sorted-arrays/)| [Golang](./content/blog/algorithm/4.md)|

content/blog/algorithm/7.md

@@ -0,0 +1,29 @@
+---
+title: 7. 整数反转
+date: '2019-11-19T21:39:00.000Z'
+---
+
+[https://leetcode-cn.com/problems/reverse-integer/](https://leetcode-cn.com/problems/reverse-integer/)
+
+使用语言：Golang
+
+```Go
+func reverse(x int) int {
+    MIN := -2147483648
+    MAX := 2147483647
+    var res int
+    for x != 0 {
+        if res * 10 < MIN || res * 10 > MAX {
+            return 0
+        }
+        y := x % 10
+        x = x / 10
+        res = res * 10 + y
+    }
+    return res
+}
+```
+
+题目很简单，反转方式就是原数不断除以 10，新数不断乘以 10，再加上原数除以 10 的余数，就能得到反转后的数。这个题目里需要注意的一点是边界判断，要注意反转后溢出的情况。
+
+