Merge pull request #105 from onemriganka/adding-Dijkstra's_Shortest_Path_Algorithm

added Dijkstra's Shortest Path Algorithm

Author: Ritikraja07

Dijkstra's Shortest Path Algorithm.java

@@ -0,0 +1,70 @@
+import java.util.*;
+
+class DijkstraAlgorithm {
+    private static final int INF = Integer.MAX_VALUE;
+
+    public static void dijkstra(int[][] graph, int source) {
+        int vertices = graph.length;
+        int[] distance = new int[vertices];
+        boolean[] visited = new boolean[vertices];
+
+        for (int i = 0; i < vertices; i++) {
+            distance[i] = INF;
+            visited[i] = false;
+        }
+
+        distance[source] = 0;
+
+        for (int i = 0; i < vertices - 1; i++) {
+            int minDistance = findMinDistance(distance, visited);
+            visited[minDistance] = true;
+
+            for (int j = 0; j < vertices; j++) {
+                if (!visited[j] && graph[minDistance][j] != 0 && distance[minDistance] != INF
+                        && distance[minDistance] + graph[minDistance][j] < distance[j]) {
+                    distance[j] = distance[minDistance] + graph[minDistance][j];
+                }
+            }
+        }
+
+        printShortestPaths(distance);
+    }
+
+    private static int findMinDistance(int[] distance, boolean[] visited) {
+        int minDistance = INF;
+        int minIndex = -1;
+        int vertices = distance.length;
+
+        for (int i = 0; i < vertices; i++) {
+            if (!visited[i] && distance[i] < minDistance) {
+                minDistance = distance[i];
+                minIndex = i;
+            }
+        }
+        return minIndex;
+    }
+
+    private static void printShortestPaths(int[] distance) {
+        int vertices = distance.length;
+        System.out.println("Vertex \t Shortest Distance from Source");
+        for (int i = 0; i < vertices; i++) {
+            System.out.println(i + " \t " + distance[i]);
+        }
+    }
+
+    public static void main(String[] args) {
+        int[][] graph = {
+            {0, 4, 0, 0, 0, 0, 0, 8, 0},
+            {4, 0, 8, 0, 0, 0, 0, 11, 0},
+            {0, 8, 0, 7, 0, 4, 0, 0, 2},
+            {0, 0, 7, 0, 9, 14, 0, 0, 0},
+            {0, 0, 0, 9, 0, 10, 0, 0, 0},
+            {0, 0, 4, 14, 10, 0, 2, 0, 0},
+            {0, 0, 0, 0, 0, 2, 0, 1, 6},
+            {8, 11, 0, 0, 0, 0, 1, 0, 7},
+            {0, 0, 2, 0, 0, 0, 6, 7, 0}
+        };
+
+        dijkstra(graph, 0);
+    }
+}