ChaseDream

标题: jj188的一点小问题 [打印本页]

作者: waterer    时间: 2006-12-21 12:18
标题: jj188的一点小问题

188. 4位数的identity number, each digit can be 0-9 inclusive, 1st digit cannot be 0, how many possible identity number

answer: 9*9*8*7

从题目叙述中,哪里可以看出identity number的每位的数字不重复呢?






欢迎光临 ChaseDream (https://forum.chasedream.com/) Powered by Discuz! X3.3