题解 | #MP3光标位置#

while True:
    try:
        n = int(input())
        cmd = input()
        playlist = [i for i in range(1, n + 1)]
        showlist = [1, 2, 3, 4]
        pt, pts = 0, 0  # pt表示只能在底部或顶部的元素在整个playlist的索引；pts表示在showlist中的指针
        for i in cmd:
            if n <= 4:
                showlist = [i for i in range(1, n + 1)]
                if i == 'U':
                    pts -= 1
                    if pts == -1:
                        # 重置 0 为 n - 1，即移动头部到尾部位置
                        pts == n - 1
                else:
                    pts += 1
                    if pts == n:
                        # 重置 n - 1 为 0，即移动尾部到头部位置
                        pts = 0
            else:
                if pts == 0:  # 处于showlist顶部
                    if i == "U":
                        if pt == 0:
                            pts = 3
                            pt = n - 1
                            showlist = playlist[pt - 3 :]
                        else:
                            pt = showlist[0] - 1 - 1 # 更新showlist，pts仍然在顶部; pt在底部
                            showlist = playlist[pt: pt + 4]
                    elif i == "D":
                        pts += 1  # 不更新showlist，仅向下移动光标即 pts + 1
                elif pts == 3:  # 处于showlist底部
                    if i == "U":
                        pts -= 1  # 不更新showlist，仅向上移动光标即 pts - 1
                    elif i == "D":
                        if pt == n - 1:
                            pts = 0
                            pt = 0
                            showlist = playlist[pt:4]
                        else:
                            pt = showlist[-1] + 1 - 1  # 更新showlist, pts仍然在底部
                            showlist = playlist[pt - 3 : pt + 1]
                else:
                    if i == "U":
                        pts -= 1  # 不更新showlist，pts - 1

                    elif i == "D":
                        pts += 1  # 不更新showlist, pts + 1
        print(" ".join(map(str, showlist)))
        print(showlist[pts])
    except:
        break