题解 | #密码截取#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String s = in.nextLine();
        char[] chars = s.toCharArray();
        int[] dp = new int[chars.length];
        dp[0] = 1;
        for (int i = 1; i < chars.length; i++) {
            dp[i] = Math.max(dp[i - 1], find(s, i, i + 1));
            dp[i] = Math.max(dp[i], find(s, i, i));
        }
        System.out.println(dp[chars.length - 1]);
    }

    public static int find(String s, int left, int right) {
        while (left >= 0 && right < s.length() && s.charAt(left) == s.charAt(right)) {
            left--;
            right++;
        }
        return right - left - 1;
    }
}