【LeetCode】958. 二叉树的完全性检验（C++ 二叉树 BFS）

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool isCompleteTree(TreeNode* root) {
        bool flag=0;///还没有遇到空节点
        bool ff=true;
        queue<TreeNode*>q;
        q.push(root);
        while(!q.empty()){
            TreeNode* now=q.front();q.pop();
            if(!now){
               flag=1;continue;
            }
            if(flag){
                ff=false;break;
            }
            q.push(now->left);
            q.push(now->right);
        }
        return ff;
    }
};