最长子回文算法

最长子回文算法简化至28行
问题：将一串字符中的最长子回文找出，请编写程序实现

源代码：

public class TheLongestPalindrome {
	public static void main(String args[]) {
		System.out.println(compute("abcdnmpoiopnjklba"));
	}
	static String compute(String s) {
		int len = s.length();
		if (len <= 0 )
			return "";
		int start = 0, end = 1;
		int arr[][] = new int[len][len];
		for (int i = 0; i < len; i++) {
			arr[i][i] = 1;
			if (i < len - 1 && s.charAt(i) == s.charAt(i + 1)) {
				arr[i][i + 1] = 1;
				start = i;
				end = 2;
			}
		}
		for (int k = 3; k <= len; k++)
			for (int i = 0, j = k + i - 1; k + i - 1 < len; i++, j = k + i - 1)
				if (s.charAt(i) == s.charAt(j) && arr[i + 1][j - 1] == 1) {
					arr[i][j] = 1;
					start = i;
					end = k;
				}
		return s.substring(start, start + end);
	}
}

运行结果：