Left View Of Binary Tree

Problem Link:

https://www.codingninjas.com/studio/problems/left-view-of-binary-tree_625707?utm_source=striver&utm_medium=website&utm_campaign=a_zcoursetuf

Hint video:

Code:

vector<int> printLeftView(BinaryTreeNode<int>* root) {
    // Write your code here.

    vector<int> view;
    queue<pair<BinaryTreeNode<int>*,int>> q;

    if(root!=NULL){
        q.push({root,0});
    }

    while(!q.empty()){
        BinaryTreeNode<int>* node = q.front().first;
        int height = q.front().second;
        q.pop();

        if(height+1>view.size()){
            view.push_back(node->data);
        }

        if(node->left!=NULL){
            q.push({node->left,height+1});
        }

        if(node->right!=NULL){
            q.push({node->right,height+1});
        }
    }

    return view;
}