public class UnweightedGraph {
private final List<String> vertexes = new ArrayList<String>();
private final Map<String, List<String>> linkTable = new TreeMap<String, List<String>>();
public List<String> getVertexes() {
return vertexes;
}
public void addVertexes(String vertex) {
if (!this.vertexes.contains(vertex.trim())) {
this.vertexes.add(vertex.trim());
}
}
public void removeVertexes(String vertex) {
this.vertexes.remove(vertex.trim());
linkTable.remove(vertex.trim());
for (Map.Entry<String, List<String>> en : this.linkTable.entrySet()) {
Iterator<String> iterator = en.getValue().iterator();
while (iterator.hasNext()) {
String next = iterator.next();
if (next.trim().equals(vertex)) {
iterator.remove();
}
}
}
}
public void addEdge(String from, String to) {
if (!this.vertexes.contains(from) || !this.vertexes.contains(to)) {
return;
}
List<String> toSet = this.linkTable.get(from);
if (toSet == null) {
toSet = new ArrayList<>();
this.linkTable.put(from, toSet);
}
if (!toSet.contains(to)) {
toSet.add(to);
}
}
public void addDoubleEdge(String from, String to) {
this.addEdge(from, to);
this.addEdge(to, from);
}
public void removeEdge(String from, String to) {
if (!this.vertexes.contains(from) || !this.vertexes.contains(to)) {
return;
}
List<String> toSet = this.linkTable.get(from);
if (toSet != null) {
toSet.remove(to);
}
}
@Override
public String toString() {
String str = "";
for (Map.Entry<String, List<String>> en : this.linkTable.entrySet()) {
str += en.getKey() + " -> [ ";
Iterator<String> iterator = en.getValue().iterator();
while (iterator.hasNext()) {
String next = iterator.next();
str += next + " ";
}
str += " ]\n";
}
return "UnweightedGraph{\n" + str + '}';
}
//深度优先
public List<String> dfs() {
if (this.vertexes.isEmpty()) {
return Collections.EMPTY_LIST;
}
List<String> results = new ArrayList<>();
Stack<String> stack = new Stack<>();
String first = this.getVertexes().get(0);
results.add(first);
stack.push(first);
while (!stack.isEmpty()) {
String top = stack.peek();
List<String> linkedVertexes = this.linkTable.get(top);
String theOne = null;
if (linkedVertexes != null) {
for (String s : linkedVertexes) {
if (!results.contains(s)) {
theOne = s;
break;
}
}
}
if (theOne == null) {
stack.pop();
} else {
results.add(theOne);
stack.push(theOne);
}
}
return results;
}
//广度优先
public List<String> bfs() {
if (this.vertexes.isEmpty()) {
return Collections.EMPTY_LIST;
}
List<String> results = new ArrayList<>();
Queue<String> queue = new LinkedList<>();
String first = this.getVertexes().get(0);
results.add(first);
queue.add(first);
while (!queue.isEmpty()) {
String top = queue.peek();
List<String> linkedVertexes = this.linkTable.get(top);
String theOne = null;
if (linkedVertexes != null) {
for (String s : linkedVertexes) {
if (!results.contains(s)) {
theOne = s;
break;
}
}
}
if (theOne == null) {
queue.poll();
} else {
results.add(theOne);
queue.add(theOne);
}
}
return results;
}
public static void main(String[] args) {
UnweightedGraph g = new UnweightedGraph();
g.addVertexes("a");
g.addVertexes("b");
g.addVertexes("c");
g.addVertexes("d");
g.addVertexes("e");
g.addDoubleEdge("a", "b");
g.addDoubleEdge("a", "c");
g.addDoubleEdge("b", "e");
g.addDoubleEdge("b", "d");
g.addDoubleEdge("c", "d");
g.addDoubleEdge("d", "e");
System.out.println(g.toString());
List<String> dfs = g.dfs();
System.out.println(dfs.toString());
List<String> bfs = g.bfs();
System.out.println(bfs.toString());
}
}
