102. Binary Tree Level Order Traversal.cpp

class Solution {
public:
vector<vector<int>>ans;
    vector<vector<int>> levelOrder(TreeNode* root) {
        vector<vector<int>>ans;
        queue<TreeNode*>q;
        q.push(root);
        if(root==NULL)
        {
            return ans;
        }
       
        while(1)
        {
            int size=q.size();
            if(size==0)
            return ans;
             vector<int>data;
             while(size>0)
             {
                 TreeNode * temp=q.front();
                 q.pop();
                 data.push_back(temp->val);
                 if(temp->left!=NULL)
                 {
                     q.push(temp->left);
                 }
                 if(temp->right!=NULL)
                 {
                     q.push(temp->right);
                 }
                 size--;
             }
             ans.push_back(data);



        }
        return ans;

       
    }
};