diff --git a/GreedyAlgorithms/Dijsktra.java b/GreedyAlgorithms/Dijsktra.java new file mode 100644 index 00000000..e8218f58 --- /dev/null +++ b/GreedyAlgorithms/Dijsktra.java @@ -0,0 +1,61 @@ +// A Java program for Dijkstra's single source shortest path algorithm. +// The program is for adjacency matrix representation of the graph +import java.util.*; +import java.lang.*; +import java.io.*; + +class Dijsktra { + static final int V = 9; + int minDistance(int dist[], Boolean sptSet[]) + { + int min = Integer.MAX_VALUE, min_index = -1; + + for (int v = 0; v < V; v++) + if (sptSet[v] == false && dist[v] <= min) { + min = dist[v]; + min_index = v; + } + + return min_index; + } + void printSolution(int dist[]) + { + System.out.println("Vertex \t\t Distance from Source"); + for (int i = 0; i < V; i++) + System.out.println(i + " \t\t " + dist[i]); + } + void dijkstra(int graph[][], int src) + { + int dist[] = new int[V]; + Boolean sptSet[] = new Boolean[V]; + for (int i = 0; i < V; i++) { + dist[i] = Integer.MAX_VALUE; + sptSet[i] = false; + } + dist[src] = 0; + + // Find shortest path for all vertices + for (int count = 0; count < V - 1; count++) { + int u = minDistance(dist, sptSet); + sptSet[u] = true; + for (int v = 0; v < V; v++) { + if (!sptSet[v] && graph[u][v] != 0 && dist[u] != Integer.MAX_VALUE && dist[u] + graph[u][v] < dist[v]) + dist[v] = dist[u] + graph[u][v]; + } + printSolution(dist); + } + public static void main(String[] args) + { + int graph[][] = new int[][] { { 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 } }; + ShortestPath t = new ShortestPath(); + t.dijkstra(graph, 0); + } +}