题解 | #最长回文子串#

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        //ccabbadc  cdabbacc abcbaaa   aaabcba
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            String str = sc.nextLine();
            int max=0;
            for(int i=0;i<str.length();i++){
                for(int j=i+2;j<=str.length();j++){
                    String sub = str.substring(i,j);
                    int subLen= sub.length();
                    if(subLen>=2){
                        //temp表示字符串的前一半 如果字符串长度是奇数,则一半的前一位
                        String temp = sub.substring(0,subLen/2);
                        //temp是表示字符串的后一半,如果是奇数,中间位留着,是中间之后的后一半
                        StringBuilder temp2= new StringBuilder(sub.substring(subLen%2==0? (subLen/2) : (subLen/2+1)));
                        temp2.reverse();//反转 和temp做对比
                        if(temp.equals(temp2.toString())){
                            max=max>sub.length()?max:sub.length();
                        }
                    }
                }
            }
            System.out.println(max);
        }
    }
}