You are given a string and are asked to write a method to return true if the string is a palindrome and to return false otherwise. A palindrome is a string that reads the same from front to back like alula They are many solutions to check if a string is a palindrome. I’m going to show you three solutions. The first will use a and the second will use a to solve the problem. For the third solution, we will solve the problem in-place. StringBuilder Character Array Solution Using StringBuilder In this solution we: Create a on line 3. StringBuilder Reverse the StringBuilder and create a new String on line 5. Use the method to see two strings are the same on line 6. equals Solution Using CharArray In this solution we: Create a new character array on line 4 using the method. toCharArray() Loop through the array on line 6. Check if the two values are not the same on line 8. If the values are not the same we return false. Return true on line 10. Solution In-Place This solution is almost the same as the last one but, we use the method to compare the characters. This solution is faster because it loops over the array at most once and does not use more memory. charAt Conclusion You have seen different ways to check if a string is a Palindrome or not in this post. If you are asked this question in a technical interview, you will have some solutions under your belt. Originally published at fluentjava.com on January 23, 2019.
