# Graph _Read this in other languages:_ [_简体中文_](README.zh-CN.md), [_Русский_](README.ru-RU.md), [_Português_](README.pt-BR.md) In computer science, a **graph** is an abstract data type that is meant to implement the undirected graph and directed graph concepts from mathematics, specifically the field of graph theory A graph data structure consists of a finite (and possibly mutable) set of vertices or nodes or points, together with a set of unordered pairs of these vertices for an undirected graph or a set of ordered pairs for a directed graph. These pairs are known as edges, arcs, or lines for an undirected graph and as arrows, directed edges, directed arcs, or directed lines for a directed graph. The vertices may be part of the graph structure, or may be external entities represented by integer indices or references.  ## References - [Wikipedia](https://en.wikipedia.org/wiki/Graph_(abstract_data_type)) - [Introduction to Graphs on YouTube](https://www.youtube.com/watch?v=gXgEDyodOJU&index=9&list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8) - [Graphs representation on YouTube](https://www.youtube.com/watch?v=k1wraWzqtvQ&index=10&list=PLLXdhg_r2hKA7DPDsunoDZ-Z769jWn4R8)