[LeetCode] 680. Valid Palindrome II 验证回文字符串 II

Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome.

Example 1:

Input: "aba"
Output: True

Example 2:

Input: "abca"
Output: True
Explanation: You could delete the character 'c'.

Note:

1. The string will only contain lowercase characters a-z. The maximum length of the string is 50000.

125. Valid Palindrome 的拓展，给定一个非空字符串，最多可删除1个字符，判断是否可以变成回文。

解法：还是从首尾两边开始比较，如果匹配就移动指针继续比较。当遇到不匹配的时候，删除左边的字符或者右边的字符，只要有一种能匹配就继续。

Python：

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class Solution(object):     def validPalindrome(self, s):         """         :type s: str         :rtype: bool         """         def validPalindrome(s, left, right):             while left < right:                 if s[left] != s[right]:                     return False                 left, right = left+1, right-1             return True                   left, right = 0, len(s)-1         while left < right:             if s[left] != s[right]:                 return validPalindrome(s, left, right-1) or validPalindrome(s, left+1, right)             left, right = left+1, right-1         return True

C++：

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class Solution { public:     bool validPalindrome(string s) {         int left = 0, right = s.length() - 1;         while (left < right) {             if (s[left] != s[right]) {                 return validPalindrome(s, left, right - 1) || validPalindrome(s, left + 1, right);             }             ++left, --right;         }         return true;     }   private:     bool validPalindrome(const string& s, int left, int right) {         while (left < right) {             if (s[left] != s[right]) {                 return false;             }             ++left, --right;         }         return true;     } };

 

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[LeetCode] 125. Valid Palindrome 验证回文字符串

 

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