680. Valid Palindrome II

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680. Valid Palindrome II

Description

Given a string s, return true if the s can be palindrome after deleting at most one character from it.

Example 1:

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Input: s = "aba"
Output: true

Example 2:

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Input: s = "abca"
Output: true
Explanation: You could delete the character 'c'.

Example 3:

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Input: s = "abc"
Output: false

Constraints:

  • 1 <= s.length <= 10^5
  • s consists of lowercase English letters.

Hints/Notes

Solution

Language: C++

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

    bool check(string s, int left, int right) {
        while (left < right) {
            if (s[left] != s[right]) {
                return false;
            }
            left++;
            right--;
        }
        return true;
    }
};