Topological Sort In Java

Topological sort is mainly used in the linear ordering of vertices in a Directed Acyclic Graph (DAG). Topological sort in Java illustrates how to do the linear ordering of vertices in programming. Here linear ordering of vertices means for every two nodes of the directed acyclic graph, v and u, such that v -> u, node v should always come before u.

Algorithm & Pseudo Code

Step I: Create the graph by calling createEdge(‘x’,’y’).

Step II: Call the topologicalSorting( )

1. Make a Boolean array (named as visit[ ]) and a stack ;
2. b: Populate the ‘false’ value to all the elements of the vist[] array. The ‘false’ value of an element means that the element is not visited. 
3. Invoke the helping function topologicalSortUtility() recursively to keep track of the Topological Sort beginning from all the vertices one by one.

Step III: Define topologicalSortUtil(char node, bool visit[], stack &stk):   

1. Update the Boolean array visit by marking the current node as visited, i.e., ‘true’ value should be added corresponding to the current node.