README_EN.md

680. Valid Palindrome II

中文文档

Description

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

 

Example 1:

Input: s = "aba"
Output: true

Example 2:

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

Example 3:

Input: s = "abc"
Output: false

 

Constraints:

• 1 <= s.length <= 105
• s consists of lowercase English letters.

Solutions

Python3

class Solution:
    def validPalindrome(self, s: str) -> bool:
        def check(i, j):
            while i < j:
                if s[i] != s[j]:
                    return False
                i, j = i + 1, j - 1
            return True

        i, j = 0, len(s) - 1
        while i < j:
            if s[i] != s[j]:
                return check(i, j - 1) or check(i + 1, j)
            i, j = i + 1, j - 1
        return True

Java

class Solution {
    public boolean validPalindrome(String s) {
        for (int i = 0, j = s.length() - 1; i < j; ++i, --j) {
            if (s.charAt(i) != s.charAt(j)) {
                return check(s, i + 1, j) || check(s, i, j - 1);
            }
        }
        return true;
    }

    private boolean check(String s, int i, int j) {
        for (; i < j; ++i, --j) {
            if (s.charAt(i) != s.charAt(j)) {
                return false;
            }
        }
        return true;
    }
}

TypeScript

function validPalindrome(s: string): boolean {
    for (let i: number = 0, j = s.length - 1; i < j; ++i, --j) {
        if (s.charAt(i) != s.charAt(j)) {
            return (
                isPalinddrome(s.slice(i, j)) ||
                isPalinddrome(s.slice(i + 1, j + 1))
            );
        }
    }
    return true;
}

function isPalinddrome(s: string): boolean {
    for (let i: number = 0, j = s.length - 1; i < j; ++i, --j) {
        if (s.charAt(i) != s.charAt(j)) {
            return false;
        }
    }
    return true;
}

C++

class Solution {
public:
    bool validPalindrome(string s) {
        for (int i = 0, j = s.size() - 1; i < j; ++i, --j)
            if (s[i] != s[j])
                return check(s, i + 1, j) || check(s, i, j - 1);
        return 1;
    }

    bool check(string s, int i, int j) {
        for (; i < j; ++i, --j)
            if (s[i] != s[j])
                return 0;
        return 1;
    }
};

Go

func validPalindrome(s string) bool {
	check := func(i, j int) bool {
		for ; i < j; i, j = i+1, j-1 {
			if s[i] != s[j] {
				return false
			}
		}
		return true
	}
	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
		if s[i] != s[j] {
			return check(i+1, j) || check(i, j-1)
		}
	}
	return true
}

JavaScript

/**
 * @param {string} s
 * @return {boolean}
 */
var validPalindrome = function (s) {
    let check = function (i, j) {
        for (; i < j; ++i, --j) {
            if (s.charAt(i) != s.charAt(j)) {
                return false;
            }
        }
        return true;
    };
    for (let i = 0, j = s.length - 1; i < j; ++i, --j) {
        if (s.charAt(i) != s.charAt(j)) {
            return check(i + 1, j) || check(i, j - 1);
        }
    }
    return true;
};

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