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Dijkstra_algo.java
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Dijkstra_algo.java
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// Dijkstra's Algorithm in Java
public class Dijkstra {
public static void dijkstra(int[][] graph, int source) {
int count = graph.length;
boolean[] visitedVertex = new boolean[count];
int[] distance = new int[count];
for (int i = 0; i < count; i++) {
visitedVertex[i] = false;
distance[i] = Integer.MAX_VALUE;
}
// Distance of self loop is zero
distance[source] = 0;
for (int i = 0; i < count; i++) {
// Update the distance between neighbouring vertex and source vertex
int u = findMinDistance(distance, visitedVertex);
visitedVertex[u] = true;
// Update all the neighbouring vertex distances
for (int v = 0; v < count; v++) {
if (!visitedVertex[v] && graph[u][v] != 0 && (distance[u] + graph[u][v] < distance[v])) {
distance[v] = distance[u] + graph[u][v];
}
}
}
for (int i = 0; i < distance.length; i++) {
System.out.println(String.format("Distance from %s to %s is %s", source, i, distance[i]));
}
}
// Finding the minimum distance
private static int findMinDistance(int[] distance, boolean[] visitedVertex) {
int minDistance = Integer.MAX_VALUE;
int minDistanceVertex = -1;
for (int i = 0; i < distance.length; i++) {
if (!visitedVertex[i] && distance[i] < minDistance) {
minDistance = distance[i];
minDistanceVertex = i;
}
}
return minDistanceVertex;
}
public static void main(String[] args) {
int graph[][] = new int[][] { { 0, 0, 1, 2, 0, 0, 0 }, { 0, 0, 2, 0, 0, 3, 0 }, { 1, 2, 0, 1, 3, 0, 0 },
{ 2, 0, 1, 0, 0, 0, 1 }, { 0, 0, 3, 0, 0, 2, 0 }, { 0, 3, 0, 0, 2, 0, 1 }, { 0, 0, 0, 1, 0, 1, 0 } };
Dijkstra T = new Dijkstra();
T.dijkstra(graph, 0);
}
}