已知一棵完全二叉树，求其节点的个数 要求：时间复杂度低于O(N)，N为这棵树的节点个数

package my_basic.class_4;

public class Code_08_CBTNode {
    // 完全二叉树的节点个数 复杂度低于O(N)

    public static class Node {
        int value;
        Node left;
        Node right;

        public Node(int value) {
            this.value = value;
        };
    }

    public static int nodeNum(Node head) {
        if (head == null) {
            return 0;
        }
        return bs(head, 1, mostLeftLevel(head, 1));
    }

    public static int bs(Node node, int level, int h) {
        if (level == h) {
            return 1;
        }
        if (mostLeftLevel(node.right, level + 1) == h) {
            System.out.println("递归中右 = h --："+(1 << (h - level) + bs(node.right, level + 1, h)));
            return (1 << (h - level)) + bs(node.right, level + 1, h);
        } else {
            System.out.println("递归中右 != h："+(1 << (h - level - 1) + bs(node.left, level + 1, h)));
            return (1 << (h - level - 1)) + bs(node.left, level + 1, h);
        }
    }

    public static int mostLeftLevel(Node node, int level) {
        while (node != null) {
            level++;
            node = node.left;
        }
        return level - 1;
    }
    
    //打印二叉树
    public static void printTree(Node head) {
        System.out.println("Binary Tree:");
        printInOrder(head, 0, "H", 17);
        System.out.println();
    }

    public static void printInOrder(Node head, int height, String to, int len) {
        if (head == null) {
            return;
        }
        printInOrder(head.right, height + 1, "v", len);
        String val = to + head.value + to;
        int lenM = val.length();
        int lenL = (len - lenM) / 2;
        int lenR = len - lenM - lenL;
        val = getSpace(lenL) + val + getSpace(lenR);
        System.out.println(getSpace(height * len) + val);
        printInOrder(head.left, height + 1, "^", len);
    }

    public static String getSpace(int num) {
        String space = " ";
        StringBuffer buf = new StringBuffer("");
        for (int i = 0; i < num; i++) {
            buf.append(space);
        }
        return buf.toString();
    }

    
    public static void main(String[] args) {
        Node head = new Node(1);
        head.left = new Node(2);
        head.right = new Node(3);
        head.left.left = new Node(4);
        head.left.right = new Node(5);
        head.right.left = new Node(6);
        System.out.println(nodeNum(head));
        
//        printTree(head);

    }
}