题解 | #MP3光标位置#

import sys

try:
    n, action = 0, ''
    while True:
        line = sys.stdin.readline().strip()
        if line == '':
            break
        lines = line.split()
        if n == 0:
            n = int(lines[0])
        else:
            action = lines[0]
    actions = list(action)
    
	# 定义当前光标
    cur = 1
	# 默认窗口
    win = [1, 2, 3, 4]
	# 上一次光标所在的位置
    pre = 1
    for ac in actions:
        if ac == 'U':
            cur = n if cur == 1 else cur - 1
        if ac == 'D':
            cur = 1 if cur == n else cur + 1
		# 首页和尾页的转换
        if pre == n and cur == 1:
            win = [1, 2, 3, 4]
        if pre == 1 and cur == n:
            win = [n-3, n-2, n-1, n]

        pre = cur
		# 如果当前编号不在窗口里面，则往窗口添加
        if cur not in win:
            win.append(cur)
            win.sort()
			# 保持窗口大小为4，根据操作UD来判断从 首或者尾 删除元素
            if ac == 'U':
                win.pop()
            if ac == 'D':
                win.pop(0)
	# 如果歌曲数量小于4
    if n < 4:
        win = [i + 1 for i in range(n)]

    page = [str(num) for num in win]
    
    print(' '.join(page))
    print(cur)

except:
    pass