题目链接:
https://leetcode.cn/problems/cong-shang-dao-xia-da-yin-er-cha-shu-ii-lcof/description/?favorite=xb9nqhhg
代码:
class Solution {
public:
vector<vector<int>>ans;
vector<vector<int>> levelOrder(TreeNode* root) {
if(root==NULL)
{
return ans;
}
queue<TreeNode*>q;
q.push(root);
while(!q.empty())
{
int num=q.size();
ans.push_back(vector<int>());
for(int i=0;i<num;i++)
{
TreeNode *top=q.front();
q.pop();
ans.back().push_back(top->val);
if(top->left) q.push(top->left);
if(top->right) q.push(top->right);
}
}
return ans;
}
};