Can i add one article in two categories?

Hello,
I wrote an article related to Android & iPhone, And I have two categories on my site Android and iPhone. So can I add the article to both categories?

Is there any problem if i add?

No problem. But why are you thinking that there will be problem?
You can created those categories then you can add any article to any category or multiple categories if it is logical as per your understanding.

i thought it might be duplicated content. if i add one article in two categories.

haha
it may happen if your all articles fall under same two set of categories. But I think it will not happen.
So do not index you category then it will not happen

Adding one article to two categories is not advisable because it creates distraction. I have experimented on one of my client blog and found a consistency in traffic improvements after splitting the articles to more relevant category.