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Copy pathBellman-Ford Algorithm
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Bellman-Ford Algorithm
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public class Main {
public static void main(String[] args) {
int noOfVertices = 5;
int startVertex=0; // A is start vertex
List<Pair<Integer,Integer>>[] adj=new ArrayList[noOfVertices];
//Pair(vertex, weight)
List<Pair<Integer,Integer>> list=new ArrayList<>();
list.add(new Pair(1,-1));
list.add(new Pair(2,4));
adj[0]=list;
list=new ArrayList<>();
list.add(new Pair(2,3));
list.add(new Pair(3,2));
list.add(new Pair(4,2));
adj[1]=list;
list=new ArrayList<>();
adj[2]=list;
list=new ArrayList<>();
list.add(new Pair(1,1));
list.add(new Pair(2,5));
adj[3]=list;
list=new ArrayList<>();
list.add(new Pair(3,-3));
adj[4]=list;
int[] path = new int[noOfVertices];
int[] distance = new int[noOfVertices];
Arrays.fill(distance,Integer.MAX_VALUE); // Intialize distance array
distance[startVertex]=0; // Making distance for start vertex 0
path[startVertex]=startVertex; // Updating path for start vertex to itself
Queue<Integer> q=new LinkedList<>();
q.add(startVertex);
while(!q.isEmpty()){
Integer vertex=q.remove();
List<Pair<Integer,Integer>> adjVertices=adj[vertex];
for(Pair<Integer,Integer> adjPair: adjVertices){
int adjVertex=adjPair.getKey();
int weight=adjPair.getValue();
int newDistance=distance[vertex] + weight;
if(distance[adjVertex]>newDistance){
distance[adjVertex]=newDistance;
path[adjVertex]=vertex;
q.add(adjVertex);
}
}
}
System.out.println("Distance from "+(char)(startVertex+'A')+" :");
for(int i=0;i<noOfVertices; i++){
System.out.print("Distance to "+(char)(i+'A')+" is "+distance[i]);
System.out.println(" from path "+(char)(path[i]+'A'));
}
}
}