Center of star graph added

Author: neha030

Data Structures/Graphs/Center_Of_Star_Graph.cpp

@@ -0,0 +1,90 @@
+/* There is an undirected star graph consisting of n nodes labeled from 1 to n.
+ A star graph is an undirected graph that has n nodes in which one is center node and  has exactly n - 1 edges.
+
+ Given a 2D integer array edges where each edges[i] = [ui, vi] indicates that there is an edge between the nodes ui and vi.
+ Return the center of the given star graph.
+    4
+    |
+    2
+   / \
+  1   3 
+  
+ Here 2 is the answer.
+ 
+ Approach: Store the nodes in vector that are connected to partciular node, if size of that vector equals to nodes-1 then 
+ print it is the centre. */
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int findCenter(vector<vector<int>>& edges)
+{
+        int n=edges.size()+1;
+        
+        vector<int>l[n+1];
+        
+        // Store the destintaion edges into source node vector
+        for(int i=0;i<edges.size();i++)
+        {
+                l[edges[i][0]].push_back(edges[i][1]);
+                l[edges[i][1]].push_back(edges[i][0]);
+        }
+         
+        // Check if vector size is equal to nodes-1, to find the center
+        int center;
+        for(int i=0;i<=n;i++)
+        {
+            if(l[i].size()==n-1)
+                center=i;
+        }
+        return center;
+}
+
+int main()
+{
+    int src,dest,no_of_edges;
+    cout<<"Enter number of edges"<<endl;
+    cin>>no_of_edges;
+    vector<vector<int>>edges;
+    
+    for(int i=0;i<no_of_edges;i++)
+    {
+        vector<int>temp;
+        
+        cout<<"Enter source of edge"<<endl;
+        cin>>src;
+        temp.push_back(src);
+        cout<<"Enter destination of edge"<<endl;
+        cin>>dest;
+        temp.push_back(dest);
+        
+        edges.push_back(temp);
+    }
+    cout<<"Center Of Star Graph : ";
+    cout<<(findCenter(edges));
+    return 0;
+}
+
+
+/* 
+INPUT:
+Enter number of edges
+3
+Enter source of edge
+1
+Enter destination of edge
+2
+Enter source of edge
+2
+Enter destination of edge
+3
+Enter source of edge
+4
+Enter destination of edge
+2
+OUTPUT:
+Center Of Star Graph : 2
+
+Time Complexity: O(no_of_edges)
+Space Complexity: O(no_of_edges)
+*/