## Depth-First and Breadth-First Search

To understand what depth-first and breadth-first search are, we must first know what graphs and directed graphs are. A **graph** is a set of objects (often called nodes) that are connected to each other. A pair of nodes is called an **edge**, and edges make up the “structure” of a graph. Put simply, a graph is a set of nodes and edges. A **directed graph** is a special instance of a graph. The difference is that in a regular (undirected) graph, the edges are bidirectional, meaning that they don’t have a specific direction. However, in a directed graph, each edge has a specified direction. ** Read more...**