Completed Dijkstra's Algorithm

Author: Vasu7052

Algorithms/Dijkstra/src/ShortestPath.java

@@ -0,0 +1,93 @@
+import java.util.Arrays;
+import java.util.Scanner;
+
+@SuppressWarnings("Duplicates")
+public class ShortestPathAdjacencyMatrix {
+
+    static class MyGraph{
+
+        int[][] adjacency_matrix ;
+        int vertices ;
+
+        MyGraph(int vertices){
+            this.vertices = vertices ;
+            this.adjacency_matrix = new int[vertices][vertices];
+        }
+
+        public void add_edge(int src, int dest , int weight){
+            adjacency_matrix[src][dest] = weight ;
+            adjacency_matrix[dest][src] = weight ;
+        }
+
+        public void display_matrix(){
+            for (int i = 0 ; i < this.vertices ; i++){
+                for (int j = 0 ; j < this.vertices ; j++){
+                    System.out.print(this.adjacency_matrix[i][j] + " ");
+                }
+                System.out.println();
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+
+        // Cross Check Graph from https://www.youtube.com/watch?v=WN3Rb9wVYDY
+
+        int vertices = 6 ;
+
+        MyGraph myGraph = new MyGraph(vertices) ;
+
+        myGraph.add_edge(0 , 1 , 4);
+        myGraph.add_edge(0 , 2 , 2);
+        myGraph.add_edge(1 , 3 , 5);
+        myGraph.add_edge(1 , 2 , 1);
+        myGraph.add_edge(2 , 3 , 8);
+        myGraph.add_edge(2 , 4 , 10);
+        myGraph.add_edge(3 , 4 , 2);
+        myGraph.add_edge(3 , 5 , 6);
+        myGraph.add_edge(4 , 5 , 3);
+
+        System.out.println("Your Adjacency Matrix : ");
+
+        myGraph.display_matrix();
+
+
+        int[] dist_arr = new int[vertices];
+        boolean[] visited = new boolean[vertices];
+
+        visited[0] = true ;
+
+        for (int i = 0 ; i < vertices ; i++){
+            if (i != 0){
+                dist_arr[i] = Integer.MAX_VALUE;
+            }
+        }
+
+        int start_node = 0 , end_node = 5 , selected_node = start_node;
+
+        System.out.print("Shortest Path -> " + selected_node);
+
+        while (!visited[end_node]){
+            int min_node = 0;
+            int min_weight = Integer.MAX_VALUE ;
+            for (int i = 0 ; i < vertices ; i++){
+                int temp_weight = myGraph.adjacency_matrix[selected_node][i] ;
+                if (temp_weight != 0 && !visited[i]){
+                    if (temp_weight < dist_arr[i]){
+                        dist_arr[i] = temp_weight ;
+                    }
+                    if (temp_weight < min_weight){
+                        min_weight = temp_weight ;
+                        min_node = i ;
+                    }
+                }
+            }
+            selected_node = min_node ;
+            visited[selected_node] = true ;
+            System.out.print(" -> " + selected_node);
+            //System.out.println(Arrays.toString(dist_arr));
+            //System.out.println(Arrays.toString(visited));
+        }
+    }
+
+}

Algorithms/Dijkstra/src/ShortestPathAdjacencyMatrix.java

@@ -1,40 +1,53 @@
 import java.util.Scanner;
 
+@SuppressWarnings("Duplicates")
 public class AdjacencyMatrix {
 
-    public static void main(String[] args) {
+    static class MyGraph{
 
-        Scanner sc = new Scanner(System.in);
+        int[][] adjacency_matrix ;
+        int vertices ;
 
-        System.out.print("Enter number of vertices : ");
+        MyGraph(int vertices){
+            this.vertices = vertices ;
+            this.adjacency_matrix = new int[vertices][vertices];
+        }
 
-        int vertices = sc.nextInt();
+        public void add_edge(int src, int dest , int weight){
+            adjacency_matrix[src][dest] = weight ;
+            adjacency_matrix[dest][src] = weight ;
+        }
 
-        int[][] adjacency_matrix = new int[vertices][vertices];
+        public void display_matrix(){
+            for (int i = 0 ; i < this.vertices ; i++){
+                for (int j = 0 ; j < this.vertices ; j++){
+                    System.out.print(this.adjacency_matrix[i][j] + " ");
+                }
+                System.out.println();
+            }
+        }
 
-        String status = "y" ;
+    }
 
-        while(status.equals("y")){
+    public static void main(String[] args) {
 
-            System.out.print("Enter the edge : ");
-            int start = sc.nextInt();
-            int end = sc.nextInt();
+        int vertices = 6 ;
 
-            adjacency_matrix[start-1][end-1] = 1 ;
-            adjacency_matrix[end-1][start-1] = 1 ;
+        MyGraph myGraph = new MyGraph(vertices) ;
 
-            System.out.print("Do you want to add another edge : ");
-            status = sc.next();
-        }
+        myGraph.add_edge(0 , 1 , 4);
+        myGraph.add_edge(0 , 2 , 2);
+        myGraph.add_edge(1 , 3 , 5);
+        myGraph.add_edge(1 , 2 , 1);
+        myGraph.add_edge(2 , 3 , 8);
+        myGraph.add_edge(2 , 4 , 10);
+        myGraph.add_edge(3 , 4 , 2);
+        myGraph.add_edge(3 , 5 , 6);
+        myGraph.add_edge(4 , 5 , 3);
 
         System.out.println("Your Adjacency Matrix : ");
 
-        for (int i = 0 ; i < vertices ; i++){
-            for (int j = 0 ; j < vertices ; j++){
-                System.out.print(adjacency_matrix[i][j] + " ");
-            }
-            System.out.println();
-        }
+        myGraph.display_matrix();
 
     }