POTD Print leaf nodes from preorder traversal of BST

//{ Driver Code Starts
//Initial Template for C++

#include <bits/stdc++.h>
using namespace std;
// } Driver Code Ends
// User function Template for C++
class Solution {
  public:
    vector<int> leafNodes(int arr[],int N) {
        // code here
          vector<int>v;
        stack<int>st;
        st.push(arr[0]);
        for(int i=1;i<N;i++){
            if(arr[i]<st.top()){
                st.push(arr[i]);
            }
            else{
                int t=st.top();
                int size=st.size();
                while(!st.empty() && arr[i]>st.top()){
                   st.pop();
                 }
                st.push(arr[i]);
                if(size>st.size()) v.push_back(t);
            }
        }
        v.push_back(st.top());
        return v;
    }
};

//{ Driver Code Starts.
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int N;
        cin >> N;
        int arr[N];
        for(int i=0;i<N;i++)cin>>arr[i];
        Solution ob;
        vector<int>ans=ob.leafNodes(arr,N);
        for(int i=0;i<ans.size();i++)cout<<ans[i]<<" ";
        cout<<endl;
    }
    return 0;
}
// } Driver Code Ends