LeetCode Count Complete Tree Nodes

Description

Given a complete binary tree, count the number of nodes.

The original problem is here.

The original code is here.

My Solution

I solve this problem in C++, as below:

/*
*Count Complete Tree Nodes 
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<stack>
#include<vector>
#include<stdlib.h>
using namespace std;
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int countNodes(TreeNode* root) {
        if(root == NULL) 
            return 0;
        int leftH  = leftHight(root) + 1;
        int rightH = rightHight(root) + 1;
        if(leftH == rightH)
            return     2<<(leftH-1) - 1;
        else
            return countNodes(root->left) + countNodes(root->right) + 1;
    }
    int leftHight(TreeNode * root){
        int hight = 0;
        while(root->left != NULL){
            root = root->left;
            hight ++;
        }
        return hight;
    }
    int rightHight(TreeNode * root){
        int hight = 0;
        while(root->right != NULL){
            root = root->right;
            hight ++;
        }
        return hight;
    }
};

Note

To solve the problem, recursion is used. If the left child and the right child have the different hight, we compute the nodes of the left and right, respectively.