二叉树

group11/252308879/dataStructure/src/main/java/org/apn/coding2017/basic/BinaryTreeNode.java

@@ -3,33 +3,74 @@
 /**
  * Created by QiPan on 2017/2/23.
  */
-public class BinaryTreeNode {
+public class BinaryTreeNode<Key extends Comparable<Key>, Value> {
 
-    private Object data;
-    private BinaryTreeNode left;
-    private BinaryTreeNode right;
+    private Node root;
 
-    public Object getData() {
-        return data;
+    private class Node {
+        private Key key;
+        private Value value;
+        private Node left, right;  //指向子树的链接
+        private int N;             // 以该节点为根的子树节点总数
+        public Node(Key key, Value value, int N) {
+            this.key = key;
+            this.value = value;
+            this.N = N;
+        }
     }
-    public void setData(Object data) {
-        this.data = data;
+
+    public int size() {
+        return size(root);
     }
-    public BinaryTreeNode getLeft() {
-        return left;
+
+    private int size(Node x) {
+        if (x == null) return 0;
+        else return x.N;
     }
-    public void setLeft(BinaryTreeNode left) {
-        this.left = left;
+
+    public Value get(Key key){
+        return get(root, key);
     }
-    public BinaryTreeNode getRight() {
-        return right;
+
+    private Value get(Node x, Key key) {
+        // 如果根节点也是Null 那么返回null
+        if (x == null){
+            return null;
+        }
+        // 拿需要查询的key 与 根节点的 key 比较
+        int cmp = key.compareTo(x.key);
+        if (cmp < 0){ // 如果小于0 那么去左子树上查询,并且递归调用
+            return get(x.left, key);
+        }else if (cmp > 0){// 如果大于0 那么去右子树上查询,并且递归调用
+            return get(x.right, key);
+        }else {
+            return x.value;
+        }
     }
-    public void setRight(BinaryTreeNode right) {
-        this.right = right;
+
+    public void push(Key key, Value value){
+        // 查询key, 找到则更新它的值，否则就创建
+        root = put(root, key, value);
     }
 
-    public BinaryTreeNode insert(Object o){
-        return  null;
+    private Node put(Node x, Key key, Value value) {
+        // 如果key 存在于以 x 为根节点的子树中 则更新它的值
+        // 否则将以key 和 value 为键值对的新节点插入到该子树中
+
+        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 { // 存在更新值
+            x.value = value;
+        }
+        // 重新统计节点总数
+        x.N = size(x.left) + size(x.right) + 1;
+        return x;
     }
 
 }