题解 | #密码截取#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner fzhinput = new Scanner(System.in);
        String zfc = fzhinput.nextLine();
        System.out.println(yxzfccd(zfc));
    }
    private static int yxzfccd(String zfc){
        int sz=0;
        boolean dtpd[][] =new boolean[zfc.length()][zfc.length()];
        if(zfc.length()<=0){
            sz=0;
        }
        for(int i=0;i<zfc.length();i++){
            dtpd[i][i]=true;
            sz=1;
        }
        for(int i=0;i<zfc.length()-1;i++){
            if(zfc.charAt(i)==zfc.charAt(i+1)){
                dtpd[i][i+1]=true;
            }
        }
        for(int l=3;l<=zfc.length();l++){
            for(int i=0;i<=zfc.length()-l;i++){
                int j = i+l-1;
                if(zfc.charAt(i)==zfc.charAt(j)&&dtpd[i+1][j-1]){
                    dtpd[i][j]=true;
                    sz = Math.max(sz,l);
                }
            }
        }

        return sz;
    }
}