问题描述
图形为： This is the graph
输出为：
输出为：1->2->4->5
但它是不正确的，因为正确答案是：
1->2->4->5->3
我的代码是用 Java 编写的，我有类 NodoG（代表图形的节点）、Grafo（代表图形）和 Principal（我在其中执行操作）。
另外，我没有考虑边的权重，我只考虑了相邻边在各自节点中的引入顺序。
例如：
- 1-> 2 权重 3：我先写
- 1-> 4 重量为 10：我把它放在第二
- 1-> 5 重量为 12：我把它排在第三
我对每个节点都这样做。但是，如果一个节点没有邻居，我不会把它写成数据。
public class NodoG {
private int dato;
boolean visitado;
List<NodoG> adyacentes;
public NodoG(int dato){
this.dato = dato;
this.visitado = false;
this.adyacentes = new ArrayList<>();
}
public int getDato() {
return dato;
}
public void setDato(int dato) {
this.dato = dato;
}
public boolean isVisitado() {
return visitado;
}
public void setVisitado(boolean visitado) {
this.visitado = visitado;
}
public List<NodoG> getAdyacentes() {
return adyacentes;
}
public void setAdyacentes(ArrayList<NodoG> adyacentes) {
this.adyacentes = adyacentes;
}
@Override
public String toString(){
return (dato + "->");
}
}
我的另一个班级：Grafo
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Scanner;
public class Grafo {
private List<NodoG> nodoGrafo;
public Grafo(){
nodoGrafo = new ArrayList<NodoG>();
}
public List<NodoG> getNodoGrafo() {
return nodoGrafo;
}
public void setNodoGrafo(ArrayList<NodoG> nodoGrafo) {
this.nodoGrafo = nodoGrafo;
}
public void insertarNodoG(){
System.out.println("Write data: ");
Scanner enTrada = new Scanner(system.in);
System.out.print("->");
int valor = enTrada.nextInt();
NodoG nodo = new NodoG(valor);
nodoGrafo.add(nodo);
}
public NodoG buscarNodoGrafo(int n1){
NodoG nodo = null;
for (NodoG nodoGrafo1 : nodoGrafo) {
if(nodoGrafo1.getDato() == n1){
nodo = nodoGrafo1;
}
}
return nodo;
}
public void insertaradyacente(){
System.out.println("Write the data of the graph's node: ");
Scanner enTrada = new Scanner(system.in);
System.out.print("->");
int valor = enTrada.nextInt();
NodoG nodo = buscarNodoGrafo(valor);
if(nodo!=null){
System.out.println("Write the data of the adjacent: ");
System.out.print("->");
int dato = enTrada.nextInt();
NodoG nuevo = new NodoG(dato);
nodo.getAdyacentes().add(nuevo);
}
else{
System.out.println("->This node doesn't exist.");
}
}
public void busquedaAmplitud(){
System.out.println("Write the initial node: ");
Scanner enTrada = new Scanner(system.in);
int dato = enTrada.nextInt();
System.out.println("-----------------------");
NodoG inicio = buscarNodoGrafo(dato);
if(inicio!=null){
Queue<NodoG> cola = new LinkedList<NodoG>();
cola.add(inicio);
inicio.setVisitado(true);
while(!cola.isEmpty()){
// System.out.println("size: "+cola.size());
NodoG elem = cola.poll();
//System.out.println("--------------");
System.out.print("->" + elem.getDato());
//System.out.println("--------------");
List<NodoG> ady = elem.getAdyacentes();
for (int i = 0;i<ady.size();i++) {
NodoG ady1 = ady.get(i);
if(ady1!= null && !ady1.isVisitado()){
cola.add(ady1);
ady1.setVisitado(true);
}
}
}
}
else{
System.out.println("This node doesn't exist.");
}
}
}
我的最后一节课：校长
import java.util.Scanner;
public class Principal {
public static void main(String[] args) {
Grafo G = new Grafo();
int opc;
System.out.println("=========================");
System.out.println("BFS");
System.out.println("=========================");
System.out.println("¿How many nodes does the graph have?: ");
Scanner enTrada = new Scanner(system.in);
int cant = enTrada.nextInt();
System.out.println("---------------------------------");
System.out.println("Write the data of the nodes: ");
for(int i=0;i<cant;i++){
G.insertarNodoG();
}
System.out.println("==================================");
System.out.println("Adjacent of the node");
System.out.println("===================================");
do{
System.out.println("Enter the node you want to write an adjacent:");
G.insertaradyacente();
System.out.println("-----------------------------------------");
System.out.print("¿Do you want to write another adjacent?: (Yes: 1) (No: Any number) -> ");
opc = enTrada.nextInt();
System.out.println("-----------------------------------");
}while(opc == 1);
do{
System.out.println("==========================");
System.out.println("BFS: ");
System.out.println("---------------------------");
G.busquedaAmplitud();
System.out.println("\n---------------------------");
//restartnodes() //To restar the boolean values of the nodes
System.out.println("¿Do you want to use another node? (Yes: 1) (No: Any number)->");
opc = enTrada.nextInt();
}while(opc==1);
}
}
请问，有人可以帮我吗？另外，我需要知道如何重新启动节点的布尔值。
解决方法
对代码进行了两个修复。首先，您的 insertarAdyacente() 函数工作不正常。因为您创建了一个新节点，而不是使用给定数据查找已创建的节点。您可以在下面找到正确的版本。
public void insertarAdyacente(){
System.out.println("Write the data of the graph's node: ");
Scanner entrada = new Scanner(System.in);
System.out.print("->");
int valor = entrada.nextInt();
NodoG nodo = buscarNodoGrafo(valor);
if(nodo!=null){
System.out.println("Write the data of the adjacent: ");
System.out.print("->");
int dato = entrada.nextInt();
NodoG nuevo = buscarNodoGrafo(dato); // fixed here.
nodo.getAdyacentes().add(nuevo);
}
else{
System.out.println("->This node doesn't exist.");
}
}
其次，我认为给所有节点一个 isVisited 字段而不是简单地在 BFS 函数中创建一个布尔数组似乎是一种不好的做法。但是我不想更改您正在应用的逻辑，而是在 Grafo 中创建了一个新函数，以便每当我们想要调用 busquedaAmplitud() 时，它都会将所有访问的设置为 False。
public void setVisitadoFalse() {
for(NodoG node: this.getNodoGrafo()) {
node.setVisitado(false);
}
}
public void busquedaAmplitud(){
this.setVisitadoFalse(); // No one is visited at the beginning.
System.out.println("Write the initial node: ");
Scanner entrada = new Scanner(System.in);
int dato = entrada.nextInt();
System.out.println("-----------------------");
NodoG inicio = buscarNodoGrafo(dato);
if(inicio!=null){
Queue<NodoG> cola = new LinkedList<NodoG>();
cola.add(inicio);
inicio.setVisitado(true);
while(!cola.isEmpty()){
NodoG elem = cola.poll();
//System.out.println("--------------");
System.out.print("->" + elem.getDato());
//System.out.println("--------------");
List<NodoG> ady = elem.getAdyacentes();
for (int i = 0;i<ady.size();i++) {
NodoG ady1 = ady.get(i);
if(ady1!= null && !ady1.isVisitado()){
cola.add(ady1);
ady1.setVisitado(true);
}
}
}
}
else{
System.out.println("This node doesn't exist.");
}
}