# Tree vs. DAG A node in a DAG can be multiply connected. For example: ``` 1 -> 2 1 -> 3 2 -> 4 3 -> 4 ``` is a DAG, but if undirected the graph would contain a cycle. A DAG can also have unconnected nodes. A tree has exactly one path between any two nodes. (Or, in a directed tree, every node has exactly one path from the root.) A DAG has a much weaker property that it is cycle-free, but there may be 0, 1, or many paths between two nodes. --- Date: 20211026 Links to: [Algorithms and Data Structures](Algorithms%20and%20Data%20Structures.md) Tags: References: * [Quora answer](https://www.quora.com/What-is-the-difference-between-a-DAG-and-a-tree-except-that-the-DAG-is-directed)