题解 | #最长回文子串#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str = in.nextLine();
        int length = 0;
        for (int i = 0; i < str.length(); i++) {
            for (int j = i; j <= str.length(); j++) {
                if (istrue(str.substring(i, j))) {
                    if (length < str.substring(i, j).length()) {
                        length = str.substring(i, j).length();
                    }
                }
            }
        }
        System.out.println(length);
    }
    public static boolean istrue(String str) {
        if (str.length() == 0) {
            return false;
        }
        int start = 0;
        int end = str.length() - 1;
        while ( start < end ) {
            char char_start = str.charAt(start);
            char char_end = str.charAt(end);
            if (char_start != char_end) {
                return false;
            }
            start++;
            end--;
        }
        return true;
    }
}