Can anyone tell me how the output of Test case 3 of Problem is —

9 9 9 15 15 6 -1 -1 6 -1 -1 -1 -1 6 15

and not —

9 9 9 -1 8 6 -1 -1 6 -1 -1 -1 8 6 8

the as far as i understand — i have to perform N moves , where -

1. Draw the topmost card from the deck. Let X be the integer written on it.
2. Then i will find a stack of upfacing cards with the smallest integer greater than or equal to X written on and and i will put this X card into that stack .
3. if there is not such stack then i will put this card into a new stack.
4. if any stack has k cards i will eat that stack.

for input —

15 3 3 14 15 9 2 6 5 13 1 7 10 11 8 12 4

According to me the steps should look like —

• 3 (new stack)
• 3 14 (two new stacks)
• 3 14 15 (three new stacks)
• 3 ( 14 9 ) 15 (9 goes to stack 2)
• (2 3) ( 14 9 ) 15 (2 goes to stack 1)
• (2 3) ( 6 14 9 ) 15 (6 goes to stack 2)
• now stack 2 to is eaten because it has size = 3 (therefore 6 , 14 , 9 is eaten at step 6)
• (2 3) (5 15) (5 goes to stack 3)
• (2 3) (13 5 15) (13 goes to stack 3)
• now stack 3 to is eaten because it has size = 3 (therefore 13 , 5 , 15 is eaten at step 8)
• .
• .
• . -and so on..

can anyone tell me where i am getting it wrong? thanks in advance