我正在开发一个搜索系统。我有这个问题，同一个Coordinate多次添加到搜索队列中。我添加了一些if语句来过滤掉这些问题，但它仍然会发生，我不知道为什么。我找不到使用LinkedHashSet的方法，因为我试图将新对象添加到列表中。
package pathFinding;
import java.util.ArrayList;
import java.util.LinkedHashSet;
public class SearchOld {
public static Boolean pathFind(Coord start, Coord end /*, ArraList<Coord> blocked*/){
boolean arrive = false;
boolean way = false;
ArrayList<Node> openList = new ArrayList<Node>();
ArrayList<Node> closedList = new ArrayList<Node>();
ArrayList<Node> adjNode = new ArrayList<Node>();
ArrayList<Coord> emptyList = new ArrayList<Coord>();
int num = 0;
Node startNode = new Node(start, start);
closedList.add(startNode);
openList.add(startNode);
System.out.println(openList.get(0).getCoord().getX() + " " + openList.get(0).getCoord().getY());
a:{while(!arrive){
all:{for(int i = 0;i<openList.size();i++){
if(end.getX() == openList.get(i).getCoord().getX() && end.getY() == openList.get(i).getCoord().getY()){
arrive = true;
break all;
}
adjNode.addAll(Adjacent.findAdjacent(openList.get(0).getCoord()));
for(int j=0;j<adjNode.size();j++){
check:{for(int k = 0;k<openList.size();k++){
if(adjNode.get(0).getCoord().getX() == openList.get(k).getCoord().getX() && adjNode.get(0).getCoord().getY() == openList.get(k).getCoord().getY()){
adjNode.remove(0);
System.err.println("X" + adjNode.get(0).getCoord().getX() + "Y" + adjNode.get(0).getCoord().getY());
arrive = true;
break check;
}else{
for(int l = 0;l<closedList.size();l++){
if(adjNode.get(0).getCoord().getX() == closedList.get(l).getCoord().getX() && adjNode.get(0).getCoord().getY() == closedList.get(l).getCoord().getY()){
/*if(end.getX() == adjNode.get(0).getCoord().getX() && end.getY() == adjNode.get(0).getCoord().getY()){
openList.add(adjNode.get(0));
closedList.add(adjNode.get(0));
break all;
}*/
adjNode.remove(0);
break check;
}else{
openList.add(adjNode.get(0));
adjNode.remove(0);
break check;
}
}
}
}}
}
closedList.add(openList.get(0));
openList.remove(0);
LinkedHashSet<Node> tempSet = new LinkedHashSet<Node>();
tempSet.addAll(closedList);
closedList.clear();
closedList.addAll(tempSet);
};}
};}
//Coordinate got add many times
for(int m = 0;m<closedList.size();m++){
if(closedList.get(m).getCoord().getX() != closedList.get(m).getParent().getX() || closedList.get(m).getCoord().getY() != closedList.get(m).getParent().getY()){
System.out.println("X"+closedList.get(m).getCoord().getX()+"Y"+closedList.get(m).getCoord().getY() +"Parent X" + closedList.get(m).getParent().getX() + "Y" + closedList.get(m).getParent().getY());
}else{
System.err.println("X"+closedList.get(m).getCoord().getX()+"Y"+closedList.get(m).getCoord().getY() +"Parent X" + closedList.get(m).getParent().getX() + "Y" + closedList.get(m).getParent().getY());
}
};
System.out.println(closedList.size());
System.out.println(arrive);
//return closedList;
return arrive;
}
}
Class Adjacent.java
public static ArrayList<Node> findAdjacent(Coord coord){
ArrayList<Node> adj = new ArrayList<Node>();
if(coord.getX() > 1){
Node left = new Node(new Coord(coord.getX()-1, coord.getY()), coord);
adj.add(left);
}
if(coord.getX() < 25){
Node right = new Node(new Coord(coord.getX()+1, coord.getY()), coord);
adj.add(right);
}
if(coord.getY() > 1){
Node up = new Node(new Coord(coord.getX(), coord.getY()-1), coord);
adj.add(up);
}
if(coord.getY() < 25){
Node down = new Node(new Coord(coord.getX(), coord.getY()+1), coord);
adj.add(down);
}
return adj;
}
评论中的那些意味着我将在以后修复此问题时添加。谢谢你的帮助。
[编辑]
我现在尝试了@Dhiraj关于改变比较坐标的比较方法的建议。但结果仍然相同，坐标不止一次添加到搜索队列。我还清理了一下代码。
Class Search.java ：
package pathFinding;
import java.util.ArrayList;
import java.util.LinkedHashSet;
public class Search {
public static Boolean pathFind(Coord start, Coord end /*, ArraList<Coord> blocked*/){
boolean arrive = false;
boolean way = false;
ArrayList<Node> openList = new ArrayList<Node>();
ArrayList<Node> closedList = new ArrayList<Node>();
ArrayList<Node> adjNode = new ArrayList<Node>();
ArrayList<Coord> emptyList = new ArrayList<Coord>();
int num = 0;
Node startNode = new Node(start, start);
closedList.add(startNode);
openList.add(startNode);
System.out.println(openList.get(0).getCoord().getX() + " " + openList.get(0).getCoord().getY());
a:{while(arrive == false){
if(CheckList.checkCoordInNodeArray(openList, end) || CheckList.checkCoordInNodeArray(closedList, end)){
arrive = true;
break;
}
all:{for(int i = 0;i<openList.size();i++){
adjNode.addAll(Adjacent.findAdjacent(openList.get(0).getCoord()));
for(int j=0;j<adjNode.size();j++){
if(CheckList.checkCoordInNodeArray(adjNode, end)){
arrive = true;
break all;
}
if(CheckList.checkCoordInNodeArray(openList, adjNode.get(0).getCoord()) == false || CheckList.checkCoordInNodeArray(closedList, adjNode.get(0).getCoord()) == false){
System.out.println("o " + CheckList.checkCoordInNodeArray(openList, adjNode.get(0).getCoord()) + " X" + adjNode.get(0).getCoord().getX() + "Y" + adjNode.get(0).getCoord().getY());
System.out.println("c " + CheckList.checkCoordInNodeArray(closedList, adjNode.get(0).getCoord())+ " X" + adjNode.get(0).getCoord().getX() + "Y" + adjNode.get(0).getCoord().getY());
openList.add(adjNode.get(0));
adjNode.remove(0);
break;
}else{
adjNode.remove(0);
break;
}
}
closedList.add(openList.get(0));
openList.remove(0);
LinkedHashSet<Node> tempSet = new LinkedHashSet<Node>();
tempSet.addAll(closedList);
closedList.clear();
closedList.addAll(tempSet);
};}
};}
//Coordinate got add many times
System.out.println("CSIZE" + closedList.size());
for(int m = 0;m<closedList.size();m++){
if(closedList.get(m).getCoord().getX() != closedList.get(m).getParent().getX() || closedList.get(m).getCoord().getY() != closedList.get(m).getParent().getY()){
System.out.println("X"+closedList.get(m).getCoord().getX()+"Y"+closedList.get(m).getCoord().getY() +"Parent X" + closedList.get(m).getParent().getX() + "Y" + closedList.get(m).getParent().getY());
}else{
System.err.println("X"+closedList.get(m).getCoord().getX()+"Y"+closedList.get(m).getCoord().getY() +"Parent X" + closedList.get(m).getParent().getX() + "Y" + closedList.get(m).getParent().getY());
}
};
System.out.println(closedList.size());
System.out.println(arrive);
//return closedList;
return arrive;
}
}
[EDIT2] 这是我的 CheckList.java
package pathFinding;
import java.util.ArrayList;
public class CheckList {
public static boolean checkNodeArray(ArrayList<Node> ar, Node no){
boolean ava = true;
for(Node node : ar){
if(no.equals(node.getCoord())){
ava = true;
}else{
ava = false;
}
}
return ava;
}
public static boolean checkCoordInNodeArray(ArrayList<Node> ar, Coord Coor){
boolean ava = true;
for(Node node : ar){
if(Node.compareNodeCoord(Coor, node)){
ava = true;
}else{
ava = false;
}
}
return ava;
}
public static Coord findCoordInNodeArray(ArrayList<Node> ar, Coord Coor){
Coord coor = Coor;
for(Node node : ar){
if(Node.compareNodeCoord(Coor, node) == true){
coor = node.getParent();
break;
}else{
}
}
if(coor == Coor){
System.err.println("NotFound");
}
return coor;
}
}
这是我的compareNodeCoord()
public static boolean compareNodeCoord(Node node1, Node node2){
boolean equal = false;
if(node1.equals(node2.getCoord())){
equal = true;
}else{
equal = false;
}
return equal;
}
public static boolean compareNodeCoord(Coord coor1, Node node2){
boolean equal = false;
if(coor1.equals(node2.getCoord())){
equal = true;
}else{
equal = false;
}
return equal;
}
这个问题不是很大，但是当我开始增加行进的块的大小时，程序将停留在非常长的循环中。
对不起，如果这看起来很乱。我是非常新的，也是使用Java编程的新手。
答案 0 :(得分：0)
您应该覆盖equals方法来比较对象。
请参考以下代码。
public static void main(String[] args) {
Coordinates c1 = new Coordinates(10, 15);
List<Coordinates> coordinatesList = new ArrayList<>();
coordinatesList.add(c1);
Coordinates c2 = new Coordinates(10, 15);
for(Coordinates coordinate:coordinatesList ){
if (coordinate.equals(c2)) {
System.out.println("Equal ");
} else {
System.out.println("Not Equal ");
}
}
}
坐标课程如下
class Coordinates{
private double x, y;
public Coordinates(double x, double y) {
this.x= x;
this.y= y;
}
// Overriding equals() to compare two Complex objects
@Override
public boolean equals(Object o) {
// If the object is compared with itself then return true
if (o == this) {
return true;
}
/* Check if o is an instance of Complex or not
"null instanceof [type]" also returns false */
if (!(o instanceof Coordinates)) {
return false;
}
// typecast o to Complex so that we can compare data members
Coordinates c = (Coordinates) o;
// Compare the data members and return accordingly
return Double.compare(x, c.x) == 0
&& Double.compare(y, c.y) == 0;
}
}
答案 1 :(得分：-1)
使用Set而不是List。不，如果将再次需要。在你自己的对象上确保它们有自己的hashCode和equals方法。