Leetcode-958 Check Completeness of a Binary Tree(二叉树的完全性检验)

模板题，不懂为什么会比第一题分高

class Solution
{
    public:
        bool isCompleteTree(TreeNode* root)
        {
            if (root == NULL)
                return false;

            queue<TreeNode *> q;
            q.push(root);
            bool mustHaveNoChild = false;
            bool result = true;
            while (!q.empty())
            {
                TreeNode* pNode = q.front();
                q.pop();
                if (mustHaveNoChild)//如果一个节点没有子节点;只要出现了空子树的节点，后面出现的必须为叶子节点（左字树右子树必须为空）
                {
                    if (pNode->left != NULL || pNode->right != NULL)
                    {
                        result = false;
                        break;
                    }
                }
                else
                {
                    if (pNode->left != NULL && pNode->right != NULL)
                    {
                        q.push(pNode->left);
                        q.push(pNode->right);
                    }
                    else if (pNode->left != NULL && pNode->right == NULL)
                    {
                        mustHaveNoChild = true;
                        q.push(pNode->left);
                    }
                    else if(pNode->left == NULL && pNode->right != NULL)
                    {
                        result = false;
                        break;
                    }
                    else
                    {
                        mustHaveNoChild = true;
                    }
                }
            }
            return result;

        }
};