Meta VO 面试真题解析：删除至多一个字符判断回文

Given a string S consisting of lowercase English characters, determine if you can make it a palindrome by removing at most 1 character.

Examples:

• tacocats → true, because removing one character gives tacocat
• abaab
• baaba

Idea:

• Use two pointers, one from the left and one from the right.
• If the characters match, continue inward.
• If they do not match, try skipping either the left character or the right character.
• If either remaining substring is a palindrome, the answer is true.

这题考察双指针判断回文的经典变体：字符串只允许删除至多一个字符，所以先从左右两端向中间扫描，一旦遇到不相等的位置，就分别尝试跳过左边字符或右边字符，再检查剩余区间是否仍是回文。这样可以在 O(n) 时间内完成判断，核心是把“最多删一个字符”的约束转化成两次局部回文验证。