【算法导论学习-24】二叉树专题2：二叉搜索树（Binary Search Tree，BST）

public class BinarySearchTreesNode<T> {
	private int key;
	private T satelliteData;
	private BinarySearchTreesNode<T> parent, leftChild, rightChild;

	public BinarySearchTreesNode(int key, T satelliteData) {
		// TODO 自动生成的构造函数存根
		this.key = key;
		this.satelliteData = satelliteData;
		parent = leftChild = rightChild = null;
	}

	public T getSatelliteData() {
		return satelliteData;
	}

	public void setSatelliteData(T satelliteData) {
		this.satelliteData = satelliteData;
	}

	public BinarySearchTreesNode<T> getParent() {
		return parent;
	}

	public void setParent(BinarySearchTreesNode<T> parent) {
		this.parent = parent;
	}

	public BinarySearchTreesNode<T> getLeftChild() {
		return leftChild;
	}

	public void setLeftChild(BinarySearchTreesNode<T> leftChild) {
		this.leftChild = leftChild;
	}

	public BinarySearchTreesNode<T> getRightChild() {
		return rightChild;
	}

	public void setRightChild(BinarySearchTreesNode<T> rightChild) {
		this.rightChild = rightChild;
	}

	public int getKey() {
		return key;

	}

}

2.     BST的建立

/**
 * @author Administrator
 * 
 */
public class BinarySearchTree<T> {
	private BinarySearchTreesNode<T> root;

	public BinarySearchTree() {
		// TODO 自动生成的构造函数存根
		root = null;
	}

	public BinarySearchTreesNode<T> getRoot() {
		return root;
	}

	public void setRoot(BinarySearchTreesNode<T> root) {
		this.root = root;
	}

	public BinarySearchTree(BinarySearchTreesNode<T> binarySearchTreesNode) {
		// TODO 自动生成的构造函数存根
		root = binarySearchTreesNode;
	}
}

二、   BST遍历

可以使用一般二叉树的遍历方法。

1.     中序遍历

	/* 算法导论288页伪代码，中序遍历， */
	public void inOrderTreeWalk(BinarySearchTreesNode<T> binarySearchTreesNode) {
		if (binarySearchTreesNode != null) {
			inOrderTreeWalk(binarySearchTreesNode.getLeftChild());
			System.out.println(binarySearchTreesNode.getKey() + ":"
					+ binarySearchTreesNode.getSatelliteData());
			inOrderTreeWalk(binarySearchTreesNode.getRightChild());
		}

	}

	public void inOrderTreeWalk() {
		inOrderTreeWalk(root);
	}

三、   BST的其他操作

public static BinarySearchTreesNode<String> getMinimum(BinarySearchTree<String> binarySearchTree) {
		BinarySearchTreesNode<String> node=binarySearchTree.getRoot();
		while (node.getLeftChild()!=null) {
			node=node.getLeftChild();
		}
		return node;	
	}

/*
	 * 算法导论294页伪代码，BinarySearchTreesNode<T>
	 * x从root开始遍历，只要binarySearchTreesNode.getKey()<x.getKey()则遍历左边，反之遍历右边
	 * 最后temp是插入位置，x=null
	 */
	public void insert(BinarySearchTreesNode<T> binarySearchTreesNode) {
		BinarySearchTreesNode<T> temp = null;
		BinarySearchTreesNode<T> x = root;
		while (x != null) {
			temp = x;
			if (binarySearchTreesNode.getKey() < x.getKey()) {
				x = x.getLeftChild();
			} else {
				x = x.getRightChild();
			}
		}
		if (temp == null) {
			root = binarySearchTreesNode;
		} else if (binarySearchTreesNode.getKey() < temp.getKey()) {
			temp.setLeftChild(binarySearchTreesNode);
		} else {
			temp.setRightChild(binarySearchTreesNode);
		}
		// System.out.println("插入完成！");
	}