LeetCode 107 Binary Tree Level Order Traversal II

题目

分析

题解

/**
* Definition for a binary tree node.
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<vector<int>> levelOrderBottom(TreeNode* root) {
vector<vector<int>> value;
if(root == NULL)
return value;
vector<TreeNode*> temp;
temp.push_back(root);
while(!temp.empty()){
vector<int> vec;
vector<TreeNode*> tree;
for(int i=0;i<temp.size();i++){
vec.push_back(temp[i]->val);
if(temp[i]->left != NULL)
tree.push_back(temp[i]->left);
if(temp[i]->right != NULL)
tree.push_back(temp[i]->right);
}
value.insert(value.begin(),vec);
temp = tree;
}
return value;
}
};