Leetcode-Solutions/MaxAreaHisto.java at master · shivammaniharsahu/Leetcode-Solutions · GitHub

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import java.util.*;

public class MaxAreaHisto
{
    public static int maxArea(int[] arr,int n)

  {

 Stack<Integer> ss=new Stack<Integer>();

 int area=0,i=0;

 int top;

 int artop;


 while(i<n)

 {

    if(ss.empty()||arr[ss.peek()]<=arr[i])

     ss.push(i++);


     else

 {

    top=ss.peek();

    ss.pop();

    artop=arr[top]*(ss.empty()?i:i-ss.peek()-1);


     if(area<artop)

       area=artop;

   }

 }

while(ss.empty()==false)

  {

      top=ss.peek();

       ss.pop();

artop=arr[top]*(ss.empty()?i:i-ss.peek()-1);


       if(area<artop)

        area=artop;


        }

return area;

 }

public static void main(String args[])
{
     Scanner sc=new Scanner(System.in);

   {
         int n=sc.nextInt();

 int[] arr=new int[n];

 for(int i=0;i<n;i++)

 {
             arr[i]=sc.nextInt();

 }


  System.out.println("Maximum area of histogram is "+maxArea(arr,n));

  }

}

}