Question

I want to determine how many items in each list are twice some other item in the same list?
For example, given the list
1 4 3 2 9 7 18 22
I should answer 3, as 2 is twice 1, 4 is twice 2, and 18 is twice 9.
for example this input
1 4 3 2 9 7 18 22 0
2 4 8 10 0
7 5 11 13 1 3 0
-1
output is
3
2
0

Answer 1

Dear visitor
Unfortunately, the statement of your question is a bit confusing.
Please clarify the statement so we could help you