102. Binary Tree Level Order Traversal
Medium
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Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).
For example:
Given binary tree [3,9,20,null,null,15,7],
3
/ \
9 20
/ \
15 7
return its level order traversal as:
[
[3],
[9,20],
[15,7]
]
class Solution {
public:
vector<vector<int>> levelOrder(TreeNode* root) {
vector<vector<int>> Result;
if(root == NULL){return Result;}
queue<TreeNode* >q;
q.push(root);
while(!q.empty()){
int Size = q.size();
vector<int> VecTemp;
for(int i = 0;i < Size;i ++){
TreeNode* Temp = q.front();
q.pop();
VecTemp.push_back(Temp->val);
if(Temp->left != NULL){q.push(Temp->left);}
if(Temp->right != NULL){q.push(Temp->right);}
}
Result.push_back(VecTemp);
}
return Result;
}
};