Traversal Algorithms:
Traversal algorithms are used to visit all the vertices and edges of a graph in a systematic manner. Two common traversal algorithms are:
- Depth-First Search (DFS):
- Starts at a designated vertex (or multiple vertices) and explores as far as possible along each branch before backtracking.
- Uses a stack or recursion to keep track of vertices to visit.
- Often used for topological sorting, cycle detection, and connectivity analysis.
- Breadth-First Search (BFS):
- Starts at a designated vertex (or multiple vertices) and explores all the neighboring vertices before moving to the next level.
- Uses a queue to keep track of vertices to visit.
- Often used for finding the shortest path, connectivity analysis, and network traversal.
Connected Component:
In a graph, a connected component is a subgraph in which every pair of vertices is connected by a path. In other words, a connected component is a maximal connected subgraph. Connectivity analysis can be performed using traversal algorithms like DFS or BFS.
Spanning Trees:
A spanning tree of a connected graph is a subgraph that is a tree and includes all the vertices of the original graph. Spanning trees are useful for understanding the structure of a graph and can be used in various applications such as network design and optimization.
Minimum Cost Spanning Trees:
In a weighted graph, a minimum cost spanning tree (MCST) is a spanning tree with the minimum total weight among all possible spanning trees. Two well-known algorithms for finding MCSTs are:
- Kruskal’s Algorithm:
- Begins with an empty set of edges and adds edges in increasing order of weight, avoiding cycles.
- Utilizes a disjoint-set data structure to efficiently detect and avoid cycles.
- Has a time complexity of O(E log E), where E is the number of edges.
- Prim’s Algorithm:
- Begins with an arbitrary vertex and repeatedly adds the shortest edge that connects a vertex in the tree to a vertex outside the tree.
- Utilizes a priority queue to efficiently select the next edge to add.
- Has a time complexity of O(E log V), where V is the number of vertices.
Both Kruskal’s and Prim’s algorithms guarantee finding the minimum cost spanning tree for a connected weighted graph. The choice between the two depends on factors such as the graph’s density, edge weights, and available data structures.