Merge pull request bhrigukansra#80 from Manvityagi/patch-4

Create Dijkstra's Algorithm

Author: Bhrigu Kansra

Graph/Dijkstra's Algorithm

@@ -0,0 +1,101 @@
+#include <iostream>
+#include<bits/stdc++.h>
+using namespace std;
+int findMinVertex(int* weights, bool* visited, int V)
+{
+  int minVertex = -1;
+  for(int i = 0; i < V; i++)
+  {
+    if(visited[i] == false)
+    {
+      if(minVertex == -1 || weights[i] < weights[minVertex])
+        minVertex = i;
+    }
+  }
+  return minVertex;
+  
+}
+void prim(int** adjMatrix, int V)
+{
+  bool* visited = new bool[V]; 
+  int*  parents = new int[V];
+  int*  weights = new int[V];
+  
+  for(int i = 0; i < V; i++){
+    weights[i] = INT_MAX;
+    visited[i] = false;
+  }
+  
+  parents[0] = -1; 
+  weights[0] = 0;
+  
+      for(int i = 0; i < V - 1; i++)
+      { //find minVertex
+        int minVertex = findMinVertex(weights,visited,V);
+        visited[minVertex] = true;
+        //explore unvisited neighbours
+        for(int j = 0; j < V; j++)
+        {
+          if(adjMatrix[minVertex][j] != 0 && !visited[j])
+          {
+            if(adjMatrix[minVertex][j] < weights[j])
+            {
+              weights[j] = adjMatrix[minVertex][j];
+              parents[j] = minVertex;
+            }        
+          }
+        }
+      }
+  
+  
+  //printing
+  for(int i = 1; i < V; i++)
+  {
+    if(parents[i] < i)
+      cout << parents[i] << " " << i << " " << weights[i] << endl;
+    else
+      cout << i << " " << parents[i] << " " << weights[i] << endl;
+
+  }
+    
+ 
+  
+  
+ }
+int main()
+{
+  int V, E, tempX, tempY;
+  cin >> V >> E;
+
+  /*
+
+  	   Write Your Code Here
+	   Complete the Rest of the Program
+	   You have to Print the output yourself
+	 
+  */
+   int ** adjMatrix = new int*[V];
+    for(int i = 0; i < V; i++)
+    {
+      adjMatrix[i] = new int[V];
+      for(int j = 0; j < V; j++)
+        adjMatrix[i][j] = 0;
+    }
+
+  
+  for(int i = 0; i<E; i++)
+  {int s,d,w;
+    cin>>s>>d>>w;
+    adjMatrix[s][d] = w;
+    adjMatrix[d][s] = w;   
+  }
+
+   prim(adjMatrix,V);
+  
+  for(int i = 0; i < V; i++)
+    delete [] adjMatrix[i];
+  
+  delete [] adjMatrix;
+
+  return 0;
+}