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.
-module(test001).
-export([print/0]).
print() -> [ {A,B,C} ||
A <- lists:seq(1,4),
B <- lists:seq(1,4),
C <- lists:seq(1,4),
A /= B,
B /= C,
A /= C
].
[{1,2,3},
{1,2,4},
{1,3,2},
{1,3,4},
{1,4,2},
{1,4,3},
{2,1,3},
{2,1,4},
{2,3,1},
{2,3,4},
{2,4,1},
{2,4,3},
{3,1,2},
{3,1,4},
{3,2,1},
{3,2,4},
{3,4,1},
{3,4,2},
{4,1,2},
{4,1,3},
{4,2,1},
{4,2,3},
{4,3,1},
{4,3,2}]