GFG_ARR_LeadersInArray.cpp

/* 
 	https://practice.geeksforgeeks.org/problems/leaders-in-an-array-1587115620/1
*/

// C++ program to remove recurring digits from
// a given number
#include <bits/stdc++.h>
using namespace std;


 // } Driver Code Ends

    

class Solution{
    //Function to find the leaders in the array.
    public:
    vector<int> leaders(int a[], int n){
        
        int myf = a[n-1]; // max_yet_from_right
        
        vector<int> ld;     // saving leaders from right
        ld.push_back(myf); //rightmost element is always leader
        
        for(int i = n-2; i>=0; i--){
            if(a[i] >= myf )     // greater than or equal to all the elements to its right side
            {
                myf=a[i];
                ld.push_back(myf);
            }
        }
        
         reverse(ld.begin(), ld.end()); // reversing saved leaders to match output
        return ld;
    }
};

// { Driver Code Starts.

int main()
{
   long long t;
   cin >> t;//testcases
   while (t--)
   {
       long long n;
       cin >> n;//total size of array
        
        int a[n];
        
        //inserting elements in the array
        for(long long i =0;i<n;i++){
            cin >> a[i];
        }
        Solution obj;
        //calling leaders() function
        vector<int> v = obj.leaders(a, n);
        
        //printing elements of the vector
        for(auto it = v.begin();it!=v.end();it++){
            cout << *it << " ";
        }
        
        cout << endl;

   }
}
  // } Driver Code Ends