getTopView

#include <bits/stdc++.h> 
/************************************************************

    Following is the TreeNode class structure:

    template <typename T>
    class TreeNode {
       public:
        T val;
        TreeNode<T> *left;
        TreeNode<T> *right;

        TreeNode(T val) {
            this->val = val;
            left = NULL;
            right = NULL;
        }
    };

************************************************************/
void topView(TreeNode<int> *root , map<int , pair<int,int>> * mp , int height,int horizontal){
    if(root==NULL) return;

    topView(root->left , mp , height+1 , horizontal-1);
    topView(root->right , mp , height+1 , horizontal+1);
    if(mp->find(horizontal) == mp->end() ){
        (*mp)[horizontal]= make_pair(root->val , height);
    }
    else{
        if((*mp)[horizontal].second >= height){
            (*mp)[horizontal]= make_pair(root->val , height);
        }
    }

}


vector<int> getTopView(TreeNode<int> *root) {
    map<int , pair<int,int>> mp;
    topView(root , &mp , 0 , 0);
    vector<int> vec;
    for (auto x : mp) {
      vec.push_back(x.second.first);
    }
    return vec;
}