数据结构 二叉查找树（java实现）

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定义：

二叉查找树（Binary Search Tree），（又：二叉搜索树，二叉排序树）它或者是一棵空树，或者是具有下列性质的二叉树： 若它的左子树不空，则左子树上所有结点的值均小于它的根结点的值； 若它的右子树不空，则右子树上所有结点的值均大于它的根结点的值； 它的左、右子树也分别为二叉排序树。

实现：

    首先看看如何实现一个二叉查找树的节点，节点类分别包含节点的数据，节点的左节点，节点的右节点，实现起来不难

public class BinaryNode<AnyType> {
    AnyType element;
    BinaryNode<AnyType> left;
    BinaryNode<AnyType> right;

    BinaryNode(AnyType theElement){
        this(theElement, null, null);
    }
    BinaryNode(AnyType theElement,BinaryNode<AnyType> lt, BinaryNode<AnyType> rt){
        element = theElement;
        left = lt;
        right = rt;
    }
}

    下面实现一个二叉查找树的类

public class BinarySearchTree<AnyType extends Comparable<? super AnyType>> {
    private BinaryNode<AnyType> root;
//    private Comparator<? super AnyType> cmp;
//    public BinarySearchTree(Comparator<?super AnyType> c){
//        root = null;
//        cmp = c;
//    }
    private static class BinaryNode<AnyType>{
        AnyType element;
        BinaryNode<AnyType> left;
        BinaryNode<AnyType> right;

        BinaryNode(AnyType theElement){
            this(theElement, null, null);
        }
        BinaryNode(AnyType theElement,BinaryNode<AnyType> lt, BinaryNode<AnyType> rt){
            element = theElement;
            left = lt;
            right = rt;
        }
    }
    public BinarySearchTree(){
        root = null;
    }
    public void makeEmpty(){
        root = null;
    }
    public boolean isEmpty(){
        return root == null;
    }
    public boolean contains(AnyType x){
        return contains(x,root);
    }
    public AnyType findMin() throws Exception {
        if(isEmpty()) throw new Exception();
        return findMin(root).element;
    }
    public AnyType findMax() throws Exception {
        if(isEmpty()) throw new Exception();
        return findMax(root).element;
    }
    public void insert(AnyType x){
        root = insert(x,root);
    }
    public void remove(AnyType x){
        root = remove(x,root);
    }
    public void printTree(){

    }
//    private int myCompare(AnyType lhs, AnyType rhs){
//        if(cmp!=null)
//            return cmp.compare(lhs,rhs);
//        else return ((Comparable)lhs).compareTo(rhs);
//    }
    private boolean contains(AnyType x , BinaryNode<AnyType> t){
        if(t == null){
            return  false;
        }
        int compareResult = x.compareTo(t.element);
        if(compareResult<0)
            return contains(x, t.left);
        else if(compareResult>0)
            return contains(x, t.right);
        else return true;
    }
    private BinaryNode<AnyType> findMin(BinaryNode<AnyType> t){
        if(t == null)
            return null;
        else if(t.left == null)
            return t;
        return findMin(t.left);

    }
    private BinaryNode<AnyType> findMax(BinaryNode<AnyType> t){
        if(t!=null)
            while (t.right!=null)
                t = t.right;
        return t;

    }
    private BinaryNode<AnyType> insert(AnyType x, BinaryNode<AnyType> t){
        if(t == null)
            return new BinaryNode<>(x , null ,null);
        int compareResult = x.compareTo(t.element);
        if(compareResult<0)
            insert(x, t.left);
        else if(compareResult>0)
            insert(x,t.right);
        else ;
        return t;
    }
    private BinaryNode<AnyType> remove(AnyType x, BinaryNode<AnyType> t){
        if(t == null)
            return t;
        int compareResult = x.compareTo(t.element);
        if(compareResult<0)
            t.left = remove(x, t.left);
        else if(compareResult>0)
            t.right = remove(x,t.right);
        else if(t.left!=null&&t.right!=null){
            t.element = findMin(t.right).element;
            t.right = remove(t.element,t.right);
        }
        else t = (t.left!=null)? t.left : t.right;
        return t;
    }
    private void print(AnyType x, BinaryNode<AnyType> t){

    }

}