AdjacencyListRepresentation.java

packageGraph;

importjava.util.ArrayList;

publicclassAdjacencyListRepresentation {

publicstaticvoidmain(String[] args) {

// adjacency list representation using dynamic sized arrays
intcapacity = 4;
ArrayList<ArrayList<Integer>> adjList = newArrayList<ArrayList<Integer>>(capacity);

for (intvertexNo = 0; vertexNo < capacity; vertexNo++) {
adjList.add(newArrayList<Integer>(vertexNo));
 }

printGraph(adjList);
System.out.println("\nadding edges..");

addEdge(adjList, 0, 1);
addEdge(adjList, 0, 2);
addEdge(adjList, 1, 2);
addEdge(adjList, 2, 3);

printGraph(adjList);
 }

privatestaticvoidaddEdge(ArrayList<ArrayList<Integer>> adj, intu, intv) {
adj.get(u).add(v);
adj.get(v).add(u);
 }

privatestaticvoidprintGraph(ArrayList<ArrayList<Integer>> adjList) {
for (inti = 0; i < adjList.size(); i++) {
System.out.println(i + ": " + adjList.get(i));
 }
 }
}

/* output:
0: []
1: []
2: []
3: []

adding edges..
0: [1, 2]
1: [0, 2]
2: [0, 1, 3]
3: [2]
*/