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Level Order Traversal Of Binary Tree.cpp
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Level Order Traversal Of Binary Tree.cpp
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// PROBLEM :- https://leetcode.com/problems/binary-tree-level-order-traversal/
// LEETCODE | MEDIUM | TREE
// Solution :- T.C. O(N) S.C. O(N)
// A classic BFS problem to attain level orders of binary tree.
class Solution {
public:
vector<vector<int>> levelOrder(TreeNode* root) {
if(root == NULL){
return {};
}
vector<vector<int>> levelOrderTraversal;
queue<TreeNode*> bfs;
bfs.push(root);
while(!bfs.empty()){
int cur_size = bfs.size();
vector<int> currentLevelOrder;
for(int i = 0 ; i < cur_size ; i++){
TreeNode* node = bfs.front();
bfs.pop();
currentLevelOrder.push_back(node->val);
if(node->left != NULL){
bfs.push(node->left);
}
if(node->right != NULL){
bfs.push(node->right);
}
}
levelOrderTraversal.push_back(currentLevelOrder);
}
return levelOrderTraversal;
}
};
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/