吸血鬼の数のアルゴリズム

package com.test;

import java.util.Arrays;

public class XiGustNumber {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		action();
	}
	public static void action(){
		int sum = 0;
		for(int i=10;i<100;i++){
			for(int j=10;j<100;j++){
				sum=i*j;
				if(sum>1000&&sum<10000&&sum%100!=0&&isEqual(sum, i, j)){					
					System.out.println(i+"*"+j+"="+sum);
				}
			}
		}
	}
	
	public static boolean isEqual(int product, int i, int j) {   
        char[] num1 = ("" + product).toCharArray();   
        char[] num2 = ("" + i + j).toCharArray();   
        Arrays.sort(num1);   
        Arrays.sort(num2);   
        return Arrays.equals(num1, num2);   
    } 

}