Binary Tree Level Order Traversal LC-102.cpp

// tc=o(n)
// sc=o(n)
class Solution {
public:
    vector<vector<int>> levelOrder(TreeNode* root) {
        if(!root) return {};
        vector<vector<int>> res;
        queue<TreeNode*> q;
        q.push(root);
        while(!q.empty()){
            int size=q.size();
            vector<int> temp;
            for(int i=0;i<size;i++){
                TreeNode* node=q.front();
                temp.push_back(node->val);
                q.pop();
                if(node->left) q.push(node->left);
                if(node->right) q.push(node->right);
            }
            res.push_back(temp);
        }
        return res;
    }
};