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  题目：有1、2、3、4个数字，能组成多少个互不相同且无重复数字的三位数？都是多少？ 1.程序分析：可填在百位、十位、个位的数字都是1、2、3、4。组成所有的排列后再去 　　　　　　掉不满足条件的排列。 (Title: There are numbers 1,2,3,4, how many can be composed of distinct three-digit numbers without repetition? Is how much? 1. Program Analysis: fill in the hundred, ten, a bit of the numbers are 1,2,3,4. Composed of all the permutations and then remove the arrangement does not meet the conditions.)