125.验证回文串

原题地址

双指针的简单题，需要注意的是只比较字母和数字，并且字母不区分大小写

python代码

def isPalindrome(self, s: str) -> bool:
    low, high = 0, len(s)-1
    while low <= high:
        while low<high and not s[low].isdigit() and not s[low].isalpha():
            low += 1
        while low<high and not s[high].isdigit() and not s[high].isalpha():
            high -= 1
        if s[low].lower() != s[high].lower():
            return False
        low += 1
        high -= 1
    return True