Я исправил проблему с помощью бесконечных циклов, но теперь, когда я пытаюсь использовать функцию find, она всегда возвращает значение null. Любые идеи о том, что происходит? Также по какой-то причине я получаю исключение NullPointerException в моей функции удаления. Пожалуйста, помогите мне здесь, ребята?реализация двоичного дерева с бесконечными циклами
package ui;
import java.time.LocalDate;
import bp.BinaryTree;
public class Main {
public static void main(String[] args) {
BinaryTree myTree = new BinaryTree();
myTree.insert(LocalDate.of(2014,12,01));
myTree.insert(LocalDate.of(2014,12,02));
myTree.insert(LocalDate.of(2014,12,03));
myTree.insert(LocalDate.of(2013,12,04));
myTree.insert(LocalDate.of(2012,12,04));
myTree.insert(LocalDate.of(2011,12,04));
myTree.insert(LocalDate.of(2010,12,04));
myTree.insert(LocalDate.of(2014,12,04));
myTree.insert(LocalDate.of(2014,12,05));
myTree.insert(LocalDate.of(2014,12,06));
myTree.insert(LocalDate.of(2014,12,07));
System.out.println(myTree);
System.out.println(myTree.getSize());
System.out.println(myTree.showMaximumValue());
System.out.println(myTree.showMinimumValue());
System.out.println(myTree.find(LocalDate.of(2014,12,07)));
}
public class BinaryTree implements IBinaryTree {
public Node root = null;
private int sizeOfTree = 0;
@Override
public LocalDate showMinimumValue() {
Node current;
Node last=null;
current = root;
while (current != null) {
last = current;
current = current.getLeftChild();
}
return last.getDate();
}
@Override
public LocalDate showMaximumValue() {
Node current;
Node last=null;
current = root;
while (current != null) {
last = current;
current = current.getRightChild();
}
return last.getDate();
}
@Override
public boolean isEmpty() {
if (root == null) {
return true;
} else
return false;
}
public int getDepth(Node n) {
int currentDepth = 0;
int depth = 0;
if (n != null) {
currentDepth++;
if (currentDepth > depth) {
depth = currentDepth;
}
getDepth(n.getLeftChild());
getDepth(n.getRightChild());
currentDepth--;
}
return depth;
}
@Override
public int getSize() {
return sizeOfTree;
}
@Override
public void clear() {
root = null;
}
@Override
public void insert(LocalDate valueToInsert) {
if (isEmpty()) {
root = new Node(valueToInsert);
sizeOfTree++;
} else {
Node n = root;
Node oldParent = null;
boolean lastDirectWasLeft = false;
sizeOfTree++;
while (n != null) {
oldParent = n;
if (valueToInsert.isBefore(n.getDate())) {
n = n.getLeftChild();
lastDirectWasLeft = true;
} else {
n = n.getRightChild();
lastDirectWasLeft = false;
}
}
if (lastDirectWasLeft) {
oldParent.setLeftChild(new Node(valueToInsert));
} else {
oldParent.setRightChild(new Node(valueToInsert));
}
}
}
@Override
public void delete(LocalDate valueToDelete) {
Node current = root;
Node parent = root;
boolean isLeftChild = true;
while (current.getDate() != valueToDelete) {
parent = current;
if (valueToDelete.isBefore(current.getDate())) {
isLeftChild = true;
current = current.getLeftChild();
} else {
isLeftChild= false;
current = current.getRightChild();
}
if (current == null) {
break;
}
}
//When there is no children, cut the string
if(current.getLeftChild().equals(null)
&& current.getRightChild().equals(null)) {
if (current == root) {
root = null;
} else if (isLeftChild) {
parent.setLeftChild(null);
} else {
parent.setRightChild(null);
}
}
//When there is no right child, replace with left child
else if (current.getRightChild().equals(null)) {
if (current == root) {
root = current.getLeftChild();
} else if (isLeftChild) {
parent.setLeftChild(current.getLeftChild());
} else
parent.setRightChild(current.getLeftChild());
}
//When there is no left child, replace with right child
else if (current.getLeftChild() == null) {
if (current == root) {
root = current.getRightChild();
} else if (isLeftChild) {
parent.setLeftChild(current.getRightChild());
} else
parent.setRightChild(current.getRightChild());
}
//has grandchildren, pass them to the grandpas
else {
//find the grandchildren
Node successor = getSuccessor(current);
if (current == root) {
root = successor;
} else if (isLeftChild) {
parent.setLeftChild(successor);
} else {
parent.setRightChild(successor);
}
//bring grandkids and granppas together
successor.setLeftChild(current.getLeftChild());
}
}
private Node getSuccessor (Node otroNode) {
Node successorParent = otroNode;
Node successor = otroNode;
Node current = otroNode.getRightChild();
while (current != null) {
successorParent = successor;
successor = current;
current = current.getLeftChild();
}
if (successor != otroNode.getRightChild()) {
successorParent.setLeftChild(successor.getRightChild());
successor.setRightChild(otroNode.getRightChild());
}
return successor;
}
@Override
public Node find(LocalDate valueToFind) {
Node current = root;
while (current.getDate() != valueToFind) {
if (valueToFind.isBefore(current.getDate())) {
current = current.getLeftChild();
} else {
current = current.getRightChild();
}
if (current == null) {
return null;
}
}
return current;
}
if (isEmpty()) {
return null;
}
if (root.getDate().isAfter(valueToFind)) {
find(root.getLeftChild().getDate());
} else if (root.getDate().isBefore(valueToFind)) {
find(root.getRightChild().getDate());
} else if (root.getDate().equals(valueToFind) ) {
return root;
}
return null;
**/
private String toString(Node todoElArbol) {
if (todoElArbol == null){
return "";
} else {
return (toString(todoElArbol.getLeftChild()) + ","
+ todoElArbol.getDate() + ","
+ toString(todoElArbol.getRightChild()))
.replaceAll(",+", ",").replaceAll("^,", "").replaceAll(",$", "");
}
}
@Override
public String toString() {
return toString(root);
}
}
Класс Node:
import java.time.LocalDate;
public class Node implements IBinaryTreeNode {
private LocalDate date;
private Node leftChild;
private Node rightChild;
public Node (LocalDate valueToInsert) {
date = valueToInsert;
}
@Override
public LocalDate getDate() {
return date;
}
@Override
public void setDate(LocalDate pDate) {
date = pDate;
}
@Override
public Node getLeftChild() {
return leftChild;
}
@Override
public void setLeftChild(Node pLeftChild) {
leftChild = pLeftChild;
}
@Override
public Node getRightChild() {
return rightChild;
}
@Override
public void setRightChild(Node pRightChild) {
rightChild = pRightChild;
}
}
по какой-то причине он по-прежнему прерывается – user2856759
@Override \t общедоступный узел (значение LocalDateToFind) {Node current = root; \t \t в то время как (IsEmpty()) { \t \t \t, если (valueToFind.isBefore (current.getDate())) { \t \t \t \t ток = current.getLeftChild(); \t \t \t} еще { \t \t \t \t ток = current.getRightChild(); \t \t \t} \t \t \t, если (текущий == NULL) { \t \t \t \t возвращение нуль; \t \t \t} \t \t} \t \t обратный ток; } – user2856759
Я никогда не просматривал весь ваш код, просто метод find ... возможно, у меня есть ошибка в моем коде, и может быть, что ваш код создания дерева тоже сломан. – rolfl