🐱(string): 125. 验证回文串

复盘

Author: JalanJiang

Diff for: docs/data-structure/array/README.md

@@ -1323,9 +1323,7 @@ func maxProfit(prices []int) int {
 
 [原题链接](https://leetcode-cn.com/problems/two-sum-ii-input-array-is-sorted/comments/)
 
-### 思路
-
-双指针
+### 解一：双指针
 
 - 指针 i 指向最左端，从左到右依次循环
 - 指针 j 指向最右端，从右到左依次循环

Diff for: docs/data-structure/string/README.md

@@ -924,6 +924,38 @@ class Solution(object):
         return True
 ```
 
+复盘：
+
+```python
+class Solution:
+    def isPalindrome(self, s: str) -> bool:
+        length = len(s)
+        i = 0
+        j = length - 1
+
+        while i < j:
+            if self.isValid(s[i]) and self.isValid(s[j]):
+                if s[i].lower() != s[j].lower():
+                    return False
+                i += 1
+                j -= 1
+            
+            if not self.isValid(s[i]):
+                i += 1
+            
+            if not self.isValid(s[j]):
+                j -= 1
+        return True
+
+    def isValid(self, c):
+        if c.isdigit() or c.isalpha():
+            return True
+        return False
+```
+
+- 时间复杂度：`O(n)`
+- 空间复杂度：`O(1)`
+
 
 ## 139. 单词拆分