If The parents are unmarried and live together with their children, the parent who pays more than half the cost of maintaining the household can file as Head of Household; the other must file as Single. With regard to claiming the children as dependents, you may split that up any way you want. But each child may only be claimed once (the same child can't be claimed by both parents).
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
