Problem 4

Problem 4

Forth problem from project Euler.
I'm not sure I like my answer to this just yet, but it runs in under a second so it can't be that bad. Feedback on better ways to do these are most welcome!

Question:

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.
Find the largest palindrome made from the product of two 3-digit numbers.

Answer:

import java.util.SortedSet;
import java.util.TreeSet;

public class problem4 {

 public static void main(String[] args) {
  
  problem4 p = new problem4();
  SortedSet set = new TreeSet();
  for(int i = 100; i < 999; i++){
   for(int j = 100; j < 999; j++){
    if(p.isPalendrome(j * i)){
     set.add(j * i);
    }
   }
  }
  System.out.println(set.last());
 }
 
 boolean isPalendrome(int num){
  String number = String.valueOf(num);
  StringBuilder sb = new StringBuilder();
  for(int i = (number.length() - 1); i >= 0; i--){
   sb.append(number.charAt(i));
  }
  if(sb.toString().equals(number)){
   return true;
  }
   return false;
 }
}