刷题记录第五十九天-求二叉树的深度非递归

层序遍历二叉树，每一层深度加一

class Solution {
public:
    int calculateDepth(TreeNode* root) {
        if(root==nullptr) return 0;
        // int left = calculateDepth(root->left);
        // int right = calculateDepth(root->right);
        // return max(left,right)+1;
        queue<TreeNode*> que;
        que.push(root);
        int depth=0;
        while(!que.empty()){
            int num=que.size();
            while(num--){
                TreeNode* node = que.front();
                que.pop();
                if(node->left)
                    que.push(node->left);
                if(node->right)
                    que.push(node->right);
            }
            depth++;
        }
        return depth;
    }
};