86 lines
2.2 KiB
Java
86 lines
2.2 KiB
Java
|
/*
|
||
|
|
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
|
||
|
|
*/
|