题解 | #MP3光标位置#

import java.util.*;
import java.io.*;
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        char[] chars = br.readLine().toCharArray();
        int head = 1; //页头歌曲
        int cursor = 1; //光标歌曲

        if (n <= 4) {
            //仅有一页时，仅需计算光标位置即可
            for (int i = 0; i < chars.length; i++) {
                cursor = cursor + chars[i] == 'U' ? 1 : -1;
            }
            cursor = cursor % n;
            cursor = cursor >= 0 ? cursor : cursor + n;
            //打印列表
            for (; head < n; head++) {
                System.out.print(head);
                System.out.print(" ");
            }
            System.out.println(head);
            //打印光标位置
            System.out.println(cursor);
            return;
        }

        for (int i = 0; i < chars.length; i++) {
            char command = chars[i];
            //遇到上一首命令
            if (command == 'U') {
                //光标在首页第一个
                if (cursor == 1) {
                    head = n - 3;
                    cursor = n;
                    continue;
                }
                //光标在其他页第一个
                if (head == cursor) {
                    head--;
                    cursor--;
                    continue;
                }
                //光标在其他页非第一个
                cursor--;
                continue;
            }
            //遇到下一首命令
            //光标在尾页最后一个
            if (cursor == n) {
                head = 1;
                cursor = 1;
                continue;
            }
            //光标在其他页最后一个
            if (cursor == head + 3) {
                head++;
                cursor++;
                continue;
            }
            //光标在其他页非最后一个
            cursor++;
        }
        for (int i = 0; i < 3; i++) {
            System.out.print(head++);
            System.out.print(" ");
        }
        System.out.println(head);
        System.out.println(cursor);
    }
}