Graph data structures and algorithms form a fundamental pillar of computer science, enabling the modeling and analysis of complex relationships and interconnected systems. A graph is a mathematical representation consisting of a set of vertices (or nodes) and edges (or links) that connect pairs of vertices. This simple yet powerful abstraction is widely used to represent networks such as social connections, transportation systems, communication networks, biological systems, and the structure of the web. Understanding graph data structures and the algorithms that operate on them is essential for solving a wide range of real-world problems efficiently. Fundamentals of Graph Data Structures At its core, a graph is defined as G = (V, E), where V represents the set of vertices and E represents the set of edges. Graphs can be classified based on various properties. For instance, a graph may be directed or undirected. In a directed graph (digraph), edges have a direction, indicating a one-w...