描述：给定字符串 num（非负整数）和整数 k，移除 k 位数字，使剩余数字最小。以字符串形式返回（不含前导零）。
3 transform chain，这一点在服务器推荐中也有详细论述
，这一点在爱思助手下载最新版本中也有详细论述
Scott spent 20 years at Tottenham until leaving two years ago after a clash with the then manager, Ange Postecoglou, who was in charge of Forest for eight matches this season.，推荐阅读旺商聊官方下载获取更多信息
AS/400 and System i, but not easily, and the first few models all suffered from