/*

Refer https://www.geeksforgeeks.org/dijkstras-shortest-path-algorithm-greedy-algo-7/

for better understanding

*/

package DataStructures.Graphs;

class dijkstras{

int k=9;

int minDist(int dist[], Boolean Set[])

{

int min = Integer.MAX_VALUE, min_index = -1;

for (int r = 0; r < k; r++)

if (Set[r] == false && dist[r] <= min) {

min = dist[r];

min_index = r;

}

return min_index;

}

void print(int dist[])

{

System.out.println("Vertex \t\t Distance");

for (int i = 0; i < k; i++)

System.out.println(i + " \t " + dist[i]);

}

void dijkstra(int graph[][], int src)

{

int dist[] = new int[k];

Boolean Set[] = new Boolean[k];

for (int i = 0; i < k; i++) {

dist[i] = Integer.MAX_VALUE;

Set[i] = false;

}

dist[src] = 0;

for (int c = 0; c < k - 1; c++) {

int u = minDist(dist, Set);

Set[u] = true;

for (int v = 0; v < k; v++)

if (!Set[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(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 } };

dijkstras t = new dijkstras();

t.dijkstra(graph, 0);

}//main

}//djikstras

/*

OUTPUT :

Vertex Distance

0 0

1 4

2 12

3 19

4 21

5 11

6 9

7 8

8 14

*/