题解 | #MP3光标位置#

while True:
    try:
        # 输入
        num_song = int(input())
        command_str = input()
        # 设置两个游标cur1 和 cur2，cur1表示的是显示屏幕上当前显示的是哪一首歌曲，cur2表示的是n首曲子中显示的是哪一首歌曲
        list_screen =[i for i in range(1,num_song+1)] 
        num_screen = 0
        if num_song < 4:
            num_screen = num_song
        else:
            num_screen =4
        cur1 = 0
        cur2 = 0
        for i in command_str:
            if i == 'U':
                if cur1 == 0 and cur2 == 0:
                    cur1 = num_screen-1
                    cur2 = num_song-1
                elif cur1 == 0 and cur2 != 0:
                    cur2 -= 1
                else:
                    cur1 -= 1
                    cur2 -= 1
            else:
                if cur1 == num_screen-1 and cur2 == num_song-1:
                    cur1 = 0
                    cur2 = 0
                elif cur1 == num_screen-1 and cur2 != num_song-1:
                    cur2 += 1
                else:
                    cur1 += 1
                    cur2 += 1
        pre = cur2
        while cur1 != 0:
            cur1 -= 1
            cur2 -= 1
        for i in range(num_screen):
            print(list_screen[cur2+i],end=' ')
        print()
        print(list_screen[pre])
    except:
        break