题解 | #最长回文子串#

import java.util.Scanner;


public class DuiChengStringLength {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = "qhbrivaighqmgafhthxicdiixpefhwwefdebwczswqqdjxulhuhceqrxechddtlbbltddhcexrqechuhluxjdqqwszcwenakceymkxfqpqxctbsousrwwhooxjtcqnvb";
//        String str = sc.nextLine();
        System.out.println(duiChengStringLength(str));
    }

    private static int duiChengStringLength(String str) {
        int maxLength = 0;
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            int from = i;
            while (str.indexOf(c, from + 1) != -1) {
                int to = str.indexOf(c, from + 1);
                int length = to - i + 1;
                if (isDuiCheng(str.substring(i, to + 1))) {
                    maxLength = Math.max(maxLength, length);
                }
                from = to;
            }
        }
        return maxLength;
    }

    private static boolean isDuiCheng(String str) {
        boolean result = true;
        int length = str.length();
        int half = length / 2;
        for (int i = 0; i < half; i++) {
            if (str.charAt(i) != str.charAt(length - 1 - i)) {
                result = false;
                break;
            }
        }
        return result;
    }
}