题解 | 小红的字符串 | Java解题

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 s = in.nextLine();
        int n = s.length();
        if (n == 1) {
            System.out.println(0);
            return;
        }
        if (n == 2) {
            int diff = Math.max(Math.abs(s.charAt(1) - s.charAt(0)),
                                Math.abs(s.charAt(0) - s.charAt(1)));
            System.out.println(diff);
            return;
        }

        String str1 = null;
        String str2 = null;
        if (n % 2 == 0) {//偶数个
            str1 = s.substring(0, n / 2);
            str2 = s.substring(n / 2, n);
        } else {//奇数个
            str1 = s.substring(0, n / 2 + 1);
            str2 = s.substring(n / 2 + 1, n);
        }
        StringBuilder sb = new StringBuilder(str1);
        sb.reverse();
        char[] cLeftArray = sb.toString().toCharArray();
        char[] cRightArray = str2.toCharArray();
        int sum = 0;
        for (int i = 0; i < cLeftArray.length; i++) {
            if (cLeftArray[i] == cRightArray[i]) {
                continue;
            } else if (cLeftArray[i] < cRightArray[i]) {
                int k = cRightArray[i] - cLeftArray[i];
                int kk = 'z' - cRightArray[i] + cLeftArray[i] - 'a' + 1;
                sum = sum + Math.min(k, kk);
            } else if (cLeftArray[i] > cRightArray[i]) {
                int k = cLeftArray[i] - cRightArray[i];
                int kk = 'z' - cLeftArray[i] + cRightArray[i] - 'a' + 1;
                sum = sum + Math.min(k, kk);
            }

        }
        System.out.println(sum);
    }
}