题解 | 判断是不是完全二叉树

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return bool布尔型
     */
    bool isCompleteTree(TreeNode* root) {
        // write code here
        TreeNode* head = root;
        if(head ==nullptr)return false;
        queue<TreeNode*> q;
        q.push(head);
        bool flag = false;
        while(!q.empty())
        {
            TreeNode* node = q.front();
            q.pop();
                if(node==nullptr)
                flag= true;
                else
                 {
                    if((flag))
                    return false;
                    q.push(node->left);
                    q.push(node->right);
                 }
            

        }
        return true;
    }
};