Leaders in an array Geeks solution

Leaders in an array Geeks solution

  July 24, 2017    

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Problem :

Write a program to print all the LEADERS in the array. An element is leader if it is greater than all the elements to its right side. The rightmost element is always a leader. 

Idea is to traverse array from right to left and check if it is greater than its next element and also greater than maximum till the index , if so push it to stack.

code:

import java.util.*;
import java.lang.*;
import java.io.*;
class GFG
 {
public static void main (String[] args)
{
Scanner ab=new Scanner(System.in);
int t=ab.nextInt();
while(t-->0)
{
   int n=ab.nextInt();
   boolean flag=false;
   int arr[]=new int[n];
   for(int i=0;i<n;i++)
   arr[i]=ab.nextInt();
   int max=arr[n-1];
   Stack<Integer> st=new Stack<Integer>();
   for(int i=n-2;i>=0;i--)
   {
       if(arr[i]>arr[i+1] && arr[i]>max)
       {
           st.push(arr[i]);
           
       }
       max=Math.max(max,arr[i]);
   }
   if(st.search(arr[n-1])==-1)
   flag=true;
   while(st.size()>0)
   System.out.print(st.pop()+" ");
   if(flag)
   System.out.print(arr[n-1]);
   System.out.println();
}
}

}