BST

纸不短，情不长

/**
 * @Classname BST
 * @Description
 * @Date 2020/1/19 10:27
 * @Author SonnSei
 */
public class BST<E extends Comparable<E>> {

    private Node root;
    private int size;

    public BST() {
        root = null;
        size = 0;
    }

    public int getSize() {
        return size;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public void add(E e) {
        root = add(root, e);
    }

    private Node add(Node node, E e) {
        if (node == null) {
            size++;
            return new Node(e);
        }
        if (e.compareTo(node.value) < 0)
            node.left = add(node.left, e);
        else if (e.compareTo(node.value) > 0)
            node.right = add(node.right, e);

        return node;
    }

    public boolean contains(E e) {
        return contains(root, e);
    }

    private boolean contains(Node node, E e) {
        if (node == null) {
            return false;
        }
        if (e.compareTo(node.value) < 0)
            return contains(node.left, e);
        if (e.compareTo(node.value) > 0)
            return contains(node.right, e);
        return true;
    }

    public E minimum() {
        if (size == 0) return null;
        return minimum(root).value;
    }

    private Node minimum(Node node) {
        if (node.left == null) return node;
        return minimum(node.left);
    }

    public E maximum() {
        if (size == 0) return null;
        return maximum(root).value;
    }

    private Node maximum(Node node) {
        if (node.right == null) return node;
        return minimum(node.right);
    }

    public E removeMin() {
        E ret = minimum();
        root = removeMin(root);
        return ret;
    }

    private Node removeMin(Node node) {
        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size--;
            return rightNode;
        }
        node.left = removeMin(node.left);
        return node;
    }

    public E removeMax() {
        E ret = maximum();
        root = removeMax(root);
        return ret;
    }

    private Node removeMax(Node node) {
        if (node.right == null) {
            Node leftNode = node.left;
            node.left = null;
            size--;
            return leftNode;
        }

        node.right = removeMin(node.right);
        return node;
    }

    public void remove(E e) {
        root = remove(root, e);
    }

    private Node remove(Node node, E e) {
        if (node == null) {
            return null;
        }

        if (e.compareTo(node.value) < 0) {
            node.left = remove(node.left, e);
            return node;
        }
        if (e.compareTo(node.value) > 0) {
            node.right = remove(node.right, e);
            return node;
        }
        if (node.left == null) {
            Node rightNode = node.right;
            node.right = null;
            size--;
            return rightNode;
        }

        if (node.right == null) {
            Node leftNode = node.left;
            node.left = null;
            size--;
            return leftNode;
        }

        Node successor = minimum(node.right);
        successor.right = removeMin(node.right);
        successor.left = node.left;
        node.left = node.right = null;
        return successor;
    }


    private class Node {
        E value;
        public Node left, right;

        public Node(E value) {
            this.value = value;
            this.left = null;
            this.right = right;
        }
    }
}

来源：CSDN

作者：SonnSei

链接：https://blog.csdn.net/weixin_40602200/article/details/104040404