题解 | #求二叉树的层序遍历#

class Solution {
public:
/*
*
* @param root TreeNode类
* @return int整型vector<vector<>>
*/
vector<vector<int> > levelOrder(TreeNode</int> root) {
vector<vector<int>>ans;
if(root==NULL)
{return ans;}
queue<TreeNode>p1,p2;
p2.push(root);
vector<int>temp;
while(!p2.empty())
{
while(!p2.empty())
{p1.push(p2.front());p2.pop();}
while(!p1.empty())
{
TreeNode</int> myroot=p1.front();
p1.pop();
temp.push_back(myroot->val);
if(myroot->left!=NULL)
{p2.push(myroot->left);}
if(myroot->right!=NULL)
{p2.push(myroot->right);}
}
ans.push_back(temp);
temp.clear();
}
return ans;
}
};</int>