Adjacency Matrix
In plain terms
A grid representing which graph nodes are connected.
Going deeper
An adjacency matrix uses a 2D table where cell [i][j] marks an edge between nodes i and j. It gives instant edge lookups but uses space proportional to nodes squared.
Under the hood
O(1) edge checks but O(V²) memory, wasteful for sparse graphs where adjacency lists are better.
Examples
Dense graphs, Floyd-Warshall, network connectivity, small fixed graphs.
Think of it like...
Like a seating chart grid marking which guests know each other.