Can someone explain in simple terms to me what a directed acyclic graph is?

Question

Can someone explain in simple terms to me what a directed acyclic graph is? I have looked on Wikipedia but it doesn\'t really make me see its use in programming.

Answer 1

A DAG is a graph where everything flows in the same direction and no node can reference back to itself.

Think of ancestry trees; they are actually DAGs.

All DAGs have

• Nodes (places to store data)
• Directed Edges (that point in the same direction)
• An ancestral node (a node without parents)
• Leaves (nodes that have no children)

DAGs are different from trees. In a tree-like structure, there must a unique path between every two nodes. In DAGs, a node can have two parent nodes.

Here's a good article about DAGs. I hope that helps.