顶

顶

慢慢列举 .

要不要分奇偶？

1）模仿全错位的推理，不知道能不能做出这道题？

n<4无解
n=4:2143,2413,3142,3412四解

1 [2, 1, 4, 5, 3]
2 [2, 1, 5, 3, 4]
3 [2, 3, 1, 5, 4]
4 [2, 3, 5, 1, 4]
5 [2, 5, 1, 3, 4]
6 [2, 5, 4, 1, 3]
7 [3, 1, 2, 5, 4]
8 [3, 1, 4, 5, 2]
9 [3, 5, 2, 1, 4]
10 [3, 5, 4, 1, 2]
11 [4, 1, 2, 5, 3]
12 [4, 1, 5, 3, 2]
13 [4, 3, 1, 5, 2]
14 [4, 3, 5, 1, 2]
15 [4, 5, 1, 3, 2]
16 [4, 5, 2, 1, 3]

这个是递推