There is a restaurant named Cafe 12. They have arranged their seats in two rows, each row consists of NNN seats. In this cafe people can come alone (single) or with his/her partner (couples). When a couple comes into this cafe they must sit in two adjacent empty seats either in the same rows or in the same column. Single people can sit in any empty seats he would like to prefer.
This is a companion discussion topic for the original entry at https://toph.co/p/cafe-12