[Coursera OA] lovely Number

http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=199644&ctid=512

https://leetcode.com/problems/count-numbers-with-unique-digits/discuss/

【推广】 免费学中医，健康全家人
原文地址：https://www.cnblogs.com/Gryffin/p/7519702.html