public class RBTree<K extends Comparable<K>, V> {public static boolean RED = true;public static boolean BLACK = false;public Node root;class Node {K key;V val;Node left, right;boolean color;int size;//高度
Node(K key, V val, boolean color, int size) {this.key = key;this.val = val;this.color = color;this.size = size;}public String toString() {return "（K:" + key + " V:" + val + " 色:" + (color==true?"红":"黑") + " s:" + size+ " 左:" + left + " 右:" + right +"）";}}public RBTree() {}public boolean isRed(Node x) {if (null == x)return false;//null是黑色return x.color == RED;}public int size(Node x) {if (x == null)return 0;return x.size;}public int size() {return size(root);}public boolean isEmpty() {return root == null;}public V get(K key) {if (key == null)throw new IllegalArgumentException();return get(root, key);}public V get(Node n, K key) {while (n != null) {if (key.compareTo(n.key) == 0)return n.val;else if (key.compareTo(n.key) < 0)n = n.left;elsen = n.right;}return null;}private Node rotateLeft(Node h) {Node x = h.right;h.right = x.left;//节点重挂x.left = h;//旋转x.color = x.left.color;x.left.color = RED;x.size = h.size;h.size = size(h.left) + size(h.right) + 1;return x;}private Node rotateRight(Node h) {//h.left和h.left.left是红色就右旋转h，Node x = h.left;h.left = x.right;//节点重挂x.right = h;//旋转x.color = x.right.color;x.right.color = RED;x.size = h.size;h.size = size(h.left) + size(h.right) + 1;return x;}private void flipColors(Node h) {// 颜色翻转h.color = !h.color;h.left.color = !h.left.color;h.right.color = !h.right.color;}public void put(K key, V val) throws Exception {if (key == null || val == null)throw new Exception();root = put(root, key, val);root.color = BLACK;}//红黑树调整是从下到上，比较路上的所有节点，依次调整，不在比较路上的节点不用调整，调整时候看的也只是左右2个子节点。private Node put(Node h, K key, V val) {//递归看形参，进去时候依次是5.0 4.0 3.0 2.0 1.0，出来时候是反过来的，依次是1.0搞完然后2.0搞完然后3.0搞完然后4.0然后5.0。if (h == null)return new Node(key, val, RED, 1);int cmp = key.compareTo(h.key);// key < h.keyif (cmp < 0) {// 放到h的左边，返回新的h的左边，因为有可能会翻转什么的，所以返回新的左节点。h.left = put(h.left, key, val);} else if (cmp > 0) {// 放到h的右边，返回新的h的右边，h.right = put(h.right, key, val);} else {h.val = val;}//每次给h增加左节点或者右节点之后，都要调整节点h。递归从下到上依次调整。if (isRed(h.right) && !isRed(h.left))// h的右节点红色，左节点是null或者黑色。节点的右边不能是红色（性质）。h = rotateLeft(h);if (isRed(h.left) && isRed(h.left.left))h = rotateRight(h);if (isRed(h.left) && isRed(h.right))flipColors(h);h.size = size(h.left) + size(h.right) + 1;return h;}public int getHeight() {return getHeight(root);}private int getHeight(Node p) {// 递归：一个函数里面依赖包含另一个函数。if (p == null)return 0;return Math.max(getHeight(p.left), getHeight(p.right)) + 1;}@SuppressWarnings("unchecked")public static void main(String[] args) throws Exception {RBTree rb = new RBTree();rb.put(5.0, 5.00);rb.put(4.0, 4.00);rb.put(3.0, 3.00);rb.put(3.5, 3.50);rb.put(2.9, 2.90);rb.put(3.6, 3.60);rb.put(3.55, 3.550);}
}