Merge pull request ephremdeme#245 from SATAKSHI08/master

added dikshtra in java

Author: ephremdeme

Algorithms/dikshtra.java

@@ -0,0 +1,97 @@
+// 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 ShortestPath { 
+// A utility function to find the vertex with minimum distance value, 
+// from the set of vertices not yet included in shortest path tree 
+static final int V = 9; 
+int minDistance(int dist[], Boolean sptSet[]) 
+{ 
+// Initialize min value 
+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; 
+} 
+
+// A utility function to print the constructed distance array 
+void printSolution(int dist[], int n) 
+{ 
+System.out.println("Vertex Distance from Source"); 
+for (int i = 0; i < V; i++) 
+System.out.println(i + " tt " + dist[i]); 
+} 
+
+// Function that implements Dijkstra's single source shortest path 
+// algorithm for a graph represented using adjacency matrix 
+// representation 
+void dijkstra(int graph[][], int src) 
+{ 
+int dist[] = new int[V]; // The output array. dist[i] will hold 
+// the shortest distance from src to i 
+
+// sptSet[i] will true if vertex i is included in shortest 
+// path tree or shortest distance from src to i is finalized 
+Boolean sptSet[] = new Boolean[V]; 
+
+// Initialize all distances as INFINITE and stpSet[] as false 
+for (int i = 0; i < V; i++) { 
+dist[i] = Integer.MAX_VALUE; 
+sptSet[i] = false; 
+} 
+
+// Distance of source vertex from itself is always 0 
+dist[src] = 0; 
+
+// Find shortest path for all vertices 
+for (int count = 0; count < V - 1; count++) { 
+// Pick the minimum distance vertex from the set of vertices 
+// not yet processed. u is always equal to src in first 
+// iteration. 
+int u = minDistance(dist, sptSet); 
+
+// Mark the picked vertex as processed 
+sptSet[u] = true; 
+
+// Update dist value of the adjacent vertices of the 
+// picked vertex. 
+for (int v = 0; v < V; v++) 
+
+// Update dist[v] only if is not in sptSet, there is an 
+// edge from u to v, and total weight of path from src to 
+// v through u is smaller than current value of dist[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]; 
+} 
+
+// print the constructed distance array 
+printSolution(dist, V); 
+} 
+
+// Driver method 
+public static void main(String[] args) 
+{ 
+/* Let us create the example graph discussed above */
+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); 
+} 
+} 
+