I can’t understand what question wants to say.

help me to understand this problem.

You have to output as minimum number of separate nested dolls as possible like In first test case

3

20 30 40 50 30 40

You see all the dolls can be fit in one doll that is {20,30} doll in {30,40} in {40,50}. so ans is 1 doll. Similarly in second test case

4

20 30 10 10 30 20 40 50

{10,10} in {20,30} and{30,20} in {40,50} (or the {20,30} doll can be fitted in {40,50} and {30,20} separate)

so there need to be 2 different nested dolls. so ans is 2

In third test case no dolls can be fitted inside. So ans is 3

In fourth test case {10,10} in {20,30} in {40,50} and {39,51} is separate. so ans is 2.

how LIS will solve this problem ? I can’t figure out/

Sort by height and keep extracting lis until you have no element left the number of times you extract is the ans I think as you would want to put as many dolls as possible in each nested doll