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package com.lab1.test3;

import com.lab1.test1.LinkedQueue;
import com.lab1.test1.LinkedStack;

public class BST<Key extends Comparable<Key>, Value> {
    private Node root;

    private class Node {
        Key key;
        Value value;
        Node left, right;
        int size;

        public Node(Key key, Value value, int size) {
            this.key = key;
            this.value = value;
            this.size = size;
        }

    }

    public Value get(Key key) {
        return get(root, key);
    }

    private Value get(Node x, Key key) {
        if (x == null) {
            return null;
        }
        int cmp = key.compareTo(x.key);
        if (cmp < 0) {
            return get(x.left, key);
        } else if (cmp > 0) {
            return get(x.right, key);
        } else {
            return x.value;
        }
    }

    public Iterable<Key> keys() {
        LinkedQueue<Key> queue = new LinkedQueue<>();
        LinkedStack<Node> stack = new LinkedStack<>();
        Node x = root;
        while (x != null || !stack.isEmpty()) {
            if (x != null) {
                stack.push(x);
                x = x.left;
            } else {
                x = stack.pop();
                queue.enqueue(x.key);
                x = x.right;
            }
        }
        return queue;
    }

    public void delete(Key key) {
        root = delete(root, key);
    }

    private Node delete(Node x, Key key) {
        if (x == null) {
            return null;
        }
        int cmp = key.compareTo(x.key);
        if (cmp < 0) {
            x.left = delete(x.left, key);
        } else if (cmp > 0) {
            x.right = delete(x.right, key);
        } else {
            if (x.left == null) {
                return x.right;
            }
            if (x.right == null) {
                return x.left;
            }
            Node t = x;
            x = min(t.right);
            x.right = deleteMin(t.right);
            x.left = t.left;
        }
        x.size = size(x.left) + size(x.right) + 1;
        return x;
    }

    public boolean contain(Key key) {
        return get(key) != null;
    }

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

    public int size() {
        return size(root);
    }

    public void deleteMin() {
        root = deleteMin(root);
    }

    private Node deleteMin(Node x) {
        if (x.left == null) {
            return x.right;
        }
        x.left = deleteMin(x.left);
        x.size = size(x.left) + size(x.right) + 1;
        return x;
    }

    public Key min() {
        return min(root).key;
    }

    private Node min(Node x) {
        if (x.left == null) {
            return x;
        }
        return min(x.left);
    }

    public int height() {
        return height(root);
    }

    private int height(Node x) {
        if (x == null) {
            return -1;
        }
        return Math.max(height(x.left), height(x.right)) + 1;
    }

    public void put(Key key, Value value) {
        root = put(root, key, value);
    }

    private Node put(Node x, Key key, Value value) {
        if (x == null) {
            return new Node(key, value, 1);
        }

        int cmp = key.compareTo(x.key);
        if (cmp < 0) {
            x.left = put(x.left, key, value);
        } else if (cmp > 0) {
            x.right = put(x.right, key, value);
        } else {
            x.value = value;
        }
        x.size = size(x.left) + size(x.right) + 1;
        return x;
    }

    public int size(Node x) {
        if (x == null) {
            return 0;
        }
        return x.size;
    }

    public Iterable<Key> levelOrder() {
        LinkedQueue<Key> keys = new LinkedQueue<>();
        LinkedQueue<Node> queue = new LinkedQueue<>();
        queue.enqueue(root);
        while (!queue.isEmpty()) {
            Node x = queue.dequeue();
            if (x == null) {
                continue;
            }
            keys.enqueue(x.key);
            queue.enqueue(x.left);
            queue.enqueue(x.right);
        }
        return keys();
    }

    private Iterable<Key> inOrder() {
        LinkedQueue<Key> queue = new LinkedQueue<>();
        root = inOrder(root, queue);
        return queue;
    }

    private Node inOrder(Node x, LinkedQueue<Key> queue) {
        if (x == null) {
            return null;
        }
        inOrder(x.left, queue);
        queue.enqueue(x.key);
        inOrder(x.right, queue);
        return x;
    }

    public static void main(String[] args) {
        BST<String, Integer> st = new BST<>();
        String test = "S E A R C H E X A M P L E";
        String[] keys = test.split(" ");
        for (int i = 0; i < keys.length; i++) {
            st.put(keys[i], i);
        }
        System.out.println("height        : " + st.height());
        System.out.println("min           : " + st.min());
        st.deleteMin();
        System.out.println("min           : " + st.min());
        System.out.println("size          : " + st.size());
        System.out.println("isEmpty       : " + st.isEmpty());
        System.out.println("contains      : " + st.contain("S"));
        st.delete("S");
        System.out.println("contains      : " + st.contain("S"));
        for (String key : st.keys()) {
            System.out.println(key + " " + st.get(key));
        }

        for (String key : st.inOrder()) {
            System.out.print(key + " ");
        }
        System.out.println();
        for (String key : st.levelOrder()) {
            System.out.print(key + " ");
        }
    }
}

输出

height        : 5
min           : A
min           : C
size          : 9
isEmpty       : false
contains      : true
contains      : false
C 4
E 12
H 5
L 11
M 9
P 10
R 3
X 7
C E H L M P R X 
C E H L M P R X 

Happy learning !!