From b95f86bbd1c3467e62ab988c5d73ed7291570220 Mon Sep 17 00:00:00 2001
From: Vanshika Jalan <vanshikajalan26@gmail.com>
Date: Sun, 20 Oct 2019 18:35:29 +0530
Subject: [PATCH] adding code to implement graph structured stack

---
 graph.cpp | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 graph.cpp

diff --git a/graph.cpp b/graph.cpp
new file mode 100644
index 0000000..23c6284
--- /dev/null
+++ b/graph.cpp
@@ -0,0 +1,127 @@
+/*
+ * C++ Program to Implement Graph Structured Stack
+ */
+#include <iostream>
+#include <cstdlib>
+#include <stack>
+#include <list>
+using namespace std;
+ 
+/*
+ * Class Graph Structured Stack
+ */
+class GraphStructuredStack
+{
+    private: 
+        list< stack<int> > stackList;
+        stack<int> mystack;
+        int numberOfNodes;
+        int **adjacencyMatrix;
+        int *parent;
+    public:
+        GraphStructuredStack(int numberOfNodes)
+        {
+            this->numberOfNodes = numberOfNodes;
+            adjacencyMatrix = new int* [numberOfNodes + 1];
+            this->parent = new int [numberOfNodes + 1];
+            for (int i = 0; i < numberOfNodes + 1; i++)
+                adjacencyMatrix[i] = new int [numberOfNodes + 1];
+        }
+        /*
+         * Implement Graph Structured Stack
+         */        
+        void graphStructuredStack(int **adjacencyMatrix, int source,int bottomNode)
+        {
+            bool stackFound = false;
+            for (int sourceVertex = 1; sourceVertex <= numberOfNodes; sourceVertex++)
+            {
+                for (int destinationVertex = 1; destinationVertex <= numberOfNodes; destinationVertex++)
+                {
+                    this->adjacencyMatrix[sourceVertex][destinationVertex] 
+                          = adjacencyMatrix[sourceVertex][destinationVertex];
+                }
+            }
+ 
+            mystack.push(source);
+            int element, destination;
+            while (!mystack.empty())
+            {
+                element = mystack.top();
+                destination = 1;
+                while (destination <= numberOfNodes)
+                {
+                    if (this->adjacencyMatrix[element][destination] == 1)
+                    {
+                        mystack.push(destination);
+                        parent[destination] = element;
+                        this->adjacencyMatrix[element][destination] = 0;
+                        if (destination == bottomNode)
+                        {
+                            stackFound = true;
+                            break;
+                        }
+                        element = destination;
+                        destination = 1;
+                        continue;
+                    }
+                    destination++;
+                }
+                if (stackFound)
+                {
+                    stack<int> istack;
+                    for (int node = bottomNode; node != source; node = parent[node])
+                    {
+                        istack.push(node);
+                    }
+                    istack.push(source);
+                    stackList.push_back(istack);
+                    stackFound = false;
+                }
+                mystack.pop();
+            }
+            list<stack<int> >::iterator iterator;
+            iterator = stackList.begin();
+            while (iterator != stackList.end())
+            {
+ 
+                stack <int> stack = *iterator;
+                iterator++;
+                while (!stack.empty())
+                {
+                    cout<<stack.top()<<"\t";
+                    stack.pop();
+                }
+                cout<<endl;
+            }
+        }
+};
+/*
+ * Main
+ */
+int main()
+{
+    int numberofnodes;
+    cout<<"Enter number of nodes: ";
+    cin>>numberofnodes;
+    GraphStructuredStack gss(numberofnodes);
+    int source, bottom;
+    int **adjacencyMatrix;
+    adjacencyMatrix = new int* [numberofnodes + 1];
+    for (int i = 0; i < numberofnodes + 1; i++)
+        adjacencyMatrix[i] = new int [numberofnodes + 1];
+    cout<<"Enter the graph matrix: "<<endl;
+    for (int sourceVertex = 1; sourceVertex <= numberofnodes; sourceVertex++)
+    {
+        for (int destinationVertex = 1; destinationVertex <= numberofnodes; destinationVertex++)
+        {
+            cin>>adjacencyMatrix[sourceVertex][destinationVertex];
+        }
+    }
+    cout<<"Enter the source node: ";
+    cin>>source;
+    cout<<"Enter the bottom node: ";
+    cin>>bottom;
+    cout<<"The stacks are: "<<endl;
+    gss.graphStructuredStack(adjacencyMatrix, source, bottom);
+    return 0;
+}
\ No newline at end of file