Place one pointer at the start and another at the end. Move them toward each other while comparing characters.

Valid Palindrome

easy

Acceptance: 56%

StringsTwo Pointers

Determine whether a given string qualifies as a palindrome after preprocessing. Preprocessing involves converting every letter to lowercase and discarding all characters that are not letters or digits. A palindrome reads identically from both ends.

Examples

Example 1:

Input:s = "Was it a car or a cat I saw"

Output:true

Explanation: After stripping non-alphanumeric characters and lowering case, the result is 'wasitacaroracatisaw', which is a palindrome.

Example 2:

Input:s = "hello world"

Output:false

Explanation: The cleaned string 'helloworld' does not read the same forwards and backwards.

Hints

1234567

import java.util.*;

public class Main {
    public static void main(String[] args) {
        // Write your solution here
    }
}

import java.util.*;

public class Main {
    public static void main(String[] args) {
        // Write your solution here
    }
}

Valid Palindrome

Examples

Hints

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