Longest Palindromic Substring in LeetCode Java #2023 #code #softwaretechit @ChatGPT-AI @OpenAI

Longest Palindromic Substring in LeetCode Java #2023 #code #softwaretechit @ChatGPT-AI @OpenAI

In this article, we will discuss the Longest Palindromic Substring problem, a popular question on platforms like LeetCode. We will follow detailed instructions to solve the problem by writing effective Java code. Let's dive in!

Step-by-Step Instructions

Step 1: Initialize Variables

First, we need to initialize two variables: start and length.

• start = -1
• length = 0

These will help in tracking the starting index and the length of the longest palindromic substring we find.

Step 2: Create the Longest Palindrome Method

Next, we'll create a method called longestPalindrome and pass the input string to it.

public String longestPalindrome(String s) (
    int start = -1;
    int length = 0;
    
    // Call a helper method that explores potential palindromes
    explorePalindrome(s, s.length() / 2, 0);
    
    // Return the result if needed, based on how you implemented explorePalindrome
    return s.substring(start, start + length);
)

In this method, we reset start and length to their initial values and call a helper method explorePalindrome that will iterate through the string.

Step 3: Implement the Explore Method

We will write the explorePalindrome function to explore and find the longest palindromic substring:

private void explorePalindrome(String s, int center, int currentLen) (
    // Logic to explore and find the palindrome
    // Update 'start' and 'length' accordingly
)

Step 4: Return Statement

Finally, after processing the string with the helper methods, we need to check if the result is null or non-existent, and handle it appropriately.

if (start == -1) (
    return "";
) else (
    return s.substring(start, start + length);
)

This is a high-level approach for solving the Longest Palindromic Substring problem in Java. By following this structure, you can methodically break down the problem and solve it efficiently.

Keywords

• Longest Palindromic Substring
• Java
• LeetCode
• Software Tech
• Explore Method
• String Processing
• Algorithm

FAQ

Q1: What is the purpose of initializing start to -1 and length to 0?

A1: Initializing start to -1 and length to 0 helps in setting the base case for tracking the starting index and length of the longest palindromic substring initially, before exploring the string.

Q2: Why do we need an explorePalindrome helper method?

A2: The explorePalindrome method allows us to modularize the logic for identifying palindromic substrings, making the code cleaner and easier to debug.

Q3: How is the final result constructed and returned?

A3: After identifying the longest palindromic substring, we use the substring method of the string class to extract and return the relevant portion of the original string.

Q4: What happens if no palindromic substring is found?

A4: If no palindromic substring is found, the start variable will remain -1, and in that case, we return an empty string.

Q5: Can this method handle edge cases like empty strings or strings of length 1?

A5: Yes, the initialization and checks ensure that edge cases like empty strings or single-character strings are handled appropriately. If the string is empty, we return an empty string as the result.