In This Post we are find shortest paths to other vertices from a given vertex in a weighted connected graph using Dijkstra’s algorithm.
5] To find shortest paths to other vertices from a given vertex in a weighted connected graph, using Dijkstra’s algorithm.
PROGRAM :-
import java.util.Scanner;
public class Dijkstras{
int d[] = new int[10];
int p[] = new int[10];
int visited[] = new int[10];
public void dijk(int[][] a, int s, int n)
{
int u = -1, v, i, j, min;
for (v = 0; v < n; v++)
{
d[v] = 99;
p[v] = -1;
}
d[s] = 0;
for (i = 0; i < n; i++)
{
min = 99;
for (j = 0; j < n; j++)
{
if (d[j] < min && visited[j] == 0)
{
min = d[j];
u = j;
}
}
visited[u] = 1;
for (v = 0; v < n; v++)
{
if ((d[u] + a[u][v] < d[v]) && (u != v) && visited[v] == 0)
{
d[v] = d[u] + a[u][v];
p[v] = u;
}
}
}
}
void path(int v, int s)
{
if (p[v] != -1)
path(p[v], s);
if (v != s)
System.out.print("->" + v + " ");
}
void display(int s, int n)
{
int i;
for (i = 0; i < n; i++)
{
if (i != s)
{
System.out.print(s + " ");
path(i, s);
}
if (i != s)
System.out.print("=" + d[i] + " ");
System.out.println();
}
}
public static void main(String[] args)
{
int a[][] = new int[10][10];
int i, j, n, s;
System.out.println("enter the number of vertices");
Scanner sc = new Scanner(System.in);
n = sc.nextInt();
System.out.println("enter the weighted matrix");
for (i = 0; i < n; i++)
for (j = 0; j < n; j++)
a[i][j] = sc.nextInt();
System.out.println("enter the source vertex");
s = sc.nextInt();
Dijkstras tr = new Dijkstras();
tr.dijk(a, s, n);
System.out.println("the shortest path between source" + s + "to remaining vertices are");
tr.display(s, n);
sc.close();
}
}