Topological Sort in Graphs
Explore how to perform a topological sort on a directed acyclic graph using recursion in C++. Understand the concept, recursive implementation, and how nodes are ordered so that each node precedes its descendants. By the end, you will be able to apply these techniques to graph problems and write recursive code that ensures correct node traversal order.
What is Topological Sort?
Topological Sort is a way to order a directed acyclic graph. A directed graph is one that has arrows that are either incoming or outgoing meaning they have direction. An acyclic graph is one that has no cycles, i.e., a node is not reachable from its own ancestors. A topological sort takes such a graph and finds the order of the nodes so that it always starts from a node with no incoming edges and then traverses its adjacent nodes. Note that this time, the current node is printed first and then its neighbors are printed. The illustration below will help you understand this concept better.
Implementing the Code
The code below shows how to do this with recursion. First, let’s see the code, then we can go on to its explanation.
Change the edges, the number of nodes n, and create your own graph, g, ...