projecteuler.net第四题

http://projecteuler.net/index.php?section=problems&id=4
projecteuler.net第四题
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.

回文数（palindromic number）的值是指类似121对称的数字，将该数按照相反的顺序排列后，所得到的数和原来的一样。找出由两个三位数相乘所得了最大回文数。

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1 楼 lampeter123 2009-07-08  

第四题答案：906609
public class Problem_4 {
       
        static boolean isPalindrome(String s) {
          StringBuffer sb = new StringBuffer(s);
          String leftStart = String.valueOf(sb);
          String rightStart = String.valueOf(sb.reverse());
          return leftStart.equals(rightStart);
        }

       
        public static void main(String args[]) {
                int max = 100 * 100;
                for (int i=100; i<1000; i++) {
                        for (int j=100; j<1000; j++) {
                                int n = i * j;
                                String s = Integer.toString(n);                       
                                if(n>max && isPalindrome(s)){
                                        max = n;
                                }
                        }
                }
                System.out.println(max);
        }
}