Create main.cpp

Author: JawadSher

23 - Graph Data Structure Problems/09 - Topological Sort using DFS/main.cpp

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+#include <bits/stdc++.h>
+using namespace std;
+
+// Function to perform DFS and topological sorting
+void topologicalSortUtil(int node, vector<vector<int> >& adj, vector<bool>& visited, stack<int>& Stack){
+  // Mark the current node as visited
+  visited[node] = true;
+
+  // Recur for all adjacent vertices
+  for (auto neighbour : adj[node]) if (!visited[neighbour]) topologicalSortUtil(neighbour, adj, visited, Stack);
+  
+  // Push current vertex to stack which stores the result
+  Stack.push(node);
+}
+
+// Function to perform Topological Sort
+void topologicalSort(vector<vector<int> >& adj, int V){
+  stack<int> Stack; // Stack to store the result
+  vector<bool> visited(V, false);
+
+  // Call the recursive helper function to store
+  // Topological Sort starting from all vertices one by
+  // one
+  for (int i = 0; i < V; i++) if (!visited[i]) topologicalSortUtil(i, adj, visited, Stack);
+
+  // Print contents of stack
+  while (!Stack.empty()) {
+    cout << Stack.top() << " ";
+    Stack.pop();
+  }
+}
+
+int main()
+{
+
+  // Number of nodes
+  int V = 4;
+
+  // Edges
+  vector<vector<int> > edges = {{0, 1}, {1, 2}, {3, 1}, {3, 2}};
+
+  // Graph represented as an adjacency list
+  vector<vector<int> > adj(V);
+
+  for (auto i : edges) adj[i[0]].push_back(i[1]);
+  
+  cout << "Topological sorting of the graph: ";
+  topologicalSort(adj, V);
+
+  return 0;
+}