680. Valid Palindrome 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:

The string will only contain lowercase characters a-z. The maximum length of the string is 50000.
题目不难，使用两次判断回文串的方法
java

class Solution {
public boolean validPalindrome(String s) {
int left = 0;
int right = s.length() - 1;
while (left < right) {
if (left < right && s.charAt(left) != s.charAt(right)) {
return isValid(s, left + 1, right) || isValid(s, left, right - 1);
} else {
left++;
right--;
}
}
return true;
}
private boolean isValid(String s, int left, int right) {
while (left < right) {
if (left < right && s.charAt(left) != s.charAt(right)) {
return false;
} else {
left++;
right--;
}
}
return true;
}
}

python

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

def isValid(self, s, left, right):
while left < right:
if left < right and s[left] != s[right]:
return False
left += 1
right -= 1
return True

java