Question

java（算法与数据结构）tree

java（算法与数据结构）tree
1Insert 3,1,4,6,9,7,5,2 into an initilly empty binary search tree and an
AVL tree.
1.1Show the process of the insertions
1.2 Use the classes of BinarySearchTree and avlNode in the
textbook,
1.) Write programs to calculate the number of leaves on the above
tWO trees.
2.) Write methods of preorder,inorder and postorder traversal,and
print the results of traversing the above two trees with 3 methods.

Answer 1

代码实现[一]部分
package ChapterEight;

class Tree {
class Node {
public long value;

public Node leftChild;

public Node rightChild;

public Node(long value) {
this.value = value;
leftChild = null;
rightChild = null;
}
}

public Node root;

public Tree() {
root = null;
}

// 向树中插入一个节点
public void insert(long value) {
Node newNode = new Node(value);
// 树是空的
if (root == null)
root = newNode;
else {
Node current = root;
Node parentNode;
while (true) {
parentNode = current;
if (value < current.value) {
current = current.leftChild;
// 要插入的节点为左孩子节点
if (current == null) {
parentNode.leftChild = newNode;
return;
}
} else {
// 要插入的节点为右孩子节点
current = current.rightChild;
if (current == null) {
parentNode.rightChild = newNode;
return;
}
}
}
}
}

// 先续遍历树中的所有节点
public void preOrder(Node currentRoot) {
if (currentRoot != null) {
System.out.print(currentRoot.value + " ");
preOrder(currentRoot.leftChild);
preOrder(currentRoot.rightChild);
}
}

// 中续遍历树中的所有节点
public void inOrder(Node currentNode) {
if (currentNode != null) {
inOrder(currentNode.leftChild);
System.out.print(currentNode.value + " ");
inOrder(currentNode.rightChild);
}
}

// 后续遍历树中的所有节点
public void postOrder(Node currentNode) {
if (currentNode != null) {
postOrder(currentNode.leftChild);
postOrder(currentNode.rightChild);
System.out.print(currentNode.value + " ");
}
}

public void traverse(int traverseType) {
switch (traverseType) {
case 1:
preOrder(root);
break;
case 2:
inOrder(root);
break;
case 3:
postOrder(root);
break;
default:
break;
}
// 依据树节点的值删除树中的一个节点
public boolean delete(int value) {
// 遍历树过程中的当前节点
Node current = root;
// 要删除节点的父节点
Node parent = root;
// 记录树的节点为左孩子节点或右孩子节点
boolean isLeftChild = true;
while (current.value != value) {
parent = current;
// 要删除的节点在当前节点的左子树里
if (value < current.value) {
isLeftChild = true;
current = current.leftChild;
}
// 要删除的节点在当前节点的右子树里
else {
isLeftChild = false;
current = current.rightChild;
}
// 在树中没有找到要删除的节点
if (current == null)
return false;
}
// 要删除的节点为叶子节点
if (current.leftChild == null && current.rightChild == null) {
// 要删除的节点为根节点
if (current == root)
root = null;
// 要删除的节点为左孩子节点
else if (isLeftChild)
parent.leftChild = null;
// 要删除的节点为右孩子节点
else
parent.rightChild = null;
}
// 要删除的节点有左孩子节点，没有右孩子节点
else if (current.rightChild == null) {
// 要删除的节点为根节点
if (current == null)
root = current.leftChild;
// 要删除的节点为左孩子节点
else if (isLeftChild)
parent.leftChild = current.leftChild;
// 要删除的节点为右孩子节点
else
parent.rightChild = current.leftChild;
}
// 要删除的节点没有左孩子节点，有右孩子节点
else if (current.leftChild == null) {
// 要删除的节点为根节点
if (current == root)
root = root.rightChild;
// 要删除的节点为左孩子节点
else if (isLeftChild)
parent.leftChild = current.rightChild;
// 要删除的节点为右孩子节点
else
parent.rightChild = current.rightChild;
}
// 要删除的接节点既有左孩子节点又有右孩子节点
else {
Node successor = getSuccessor(current);
// 要删除的节点为根节点
if (current == root)
root = successor;
// 要删除的节点为左孩子节点
else if (isLeftChild)
parent.leftChild = successor;
// 要删除的节点为右孩子节点
else
parent.rightChild = successor;
}
return true;
}

// 找到要删除节点的替补节点
private Node getSuccessor(Node delNode) {
// 替补节点的父节点
Node successorParent = delNode;
// 删除节点的替补节点
Node successor = delNode;
Node current = delNode.rightChild;
while (current != null) {
// successorParent指向当前节点的上一个节点
successorParent = successor;
// successor变为当前节点
successor = current;
current = current.leftChild;
}
// 替补节点的右孩子节点不为空
if (successor != delNode.rightChild) {
successorParent.leftChild = successor.rightChild;
successor.rightChild = delNode.rightChild;
}
return successor;
}
}

public class TreeApp {
public static void main(String[] args) {
Tree tree = new Tree();
tree.insert(8);
tree.insert(50);
tree.insert(45);
tree.insert(21);
tree.insert(32);
tree.insert(18);
tree.insert(37);
tree.insert(64);
tree.insert(88);
tree.insert(5);
tree.insert(4);
tree.insert(7);

System.out.print("PreOrder : ");
tree.traverse(1);
System.out.println();

System.out.print("InOrder : ");
tree.traverse(2);
System.out.println();

System.out.print("PostOrder : ");
tree.traverse(3);
System.out.println();

System.out.println(tree.delete(7));

System.out.print("PreOrder : ");
tree.traverse(1);
System.out.println();

System.out.print("InOrder : ");
tree.traverse(2);
System.out.println();

System.out.print("PostOrder : ");
tree.traverse(3);
System.out.println();

}
}