Graph

Graphs provide a clear and precise way to represent various problems. For example, determining the minimum number of colors needed to color a political map, ensuring that neighboring countries have different colors, can be simplified by using a graph where each vertex represents a country and edges connect neighboring countries. This eliminates irrelevant details like intricate boundaries and rivers.

Graph coloring is also useful for other problems, such as scheduling university exams with the fewest time slots. Each exam is a vertex, and edges represent conflicts where a student is taking both exams. Assigning time slots is equivalent to coloring the graph.

Graph operations are common in many contexts, leading to the development of efficient algorithms to uncover the basic connectivity structure of graphs. A graph consists of vertices (nodes) and edges (connections between nodes). For example, in a map, vertices represent countries and edges represent shared borders. These edges are undirected, meaning the relationship is mutual.

In some cases, graphs use directed edges, indicating one-way relationships, such as the graph of all links on the World Wide Web. This enormous directed graph has billions of nodes and edges, with each vertex representing a site and each directed edge representing a link from one site to another. Understanding the connectivity properties of such a large graph is important and can often be achieved in linear time, providing valuable insights.