[2,3,4,5]
4
[2,3,4,5]是最长子数组
[2,2,3,4,3]
3
[2,3,4]是最长子数组
[9]
1
[1,2,3,1,2,3,2,2]
最长子数组为[1,2,3]
[2,2,3,4,8,99,3]
5
最长子数组为[2,3,4,8,99]