Print Common Nodes in BST Geeks solution

Print Common Nodes in BST Geeks solution

  July 22, 2017    

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Problem :
 Given two Binary Search Trees, task is to complete the function printCommon, which print's the common nodes in them. In other words, find intersection of two BSTs.

Solution : FInd inorder of both trees and save them in 2 arraylist and check with a loop for common elements

Code:



/*Complete the function below
Node is as follows:
class Node{
int data;
Node left,right;
Node (int d){
data=d;
left=right=null;
}
}
*/
class hackerranksolutionc
{
    List<Integer> arr=new ArrayList<Integer>();
    List<Integer>arr2=new ArrayList<Integer>();
    public void inorder(Node root,boolean flag)
    {
        if(root==null)
        return;
        if(flag)
        arr.add(root.data);
        else
        arr2.add(root.data);
        inorder(root.left,flag);
        inorder(root.right,flag);
       
    }
public void printCommon(Node root1,Node root2)
         {
         inorder(root1,false);
         inorder(root2,true);
         Collections.sort(arr2);
         for(int i=0;i<arr2.size();i++)
         {
             if(arr.contains(arr2.get(i)))
             System.out.print(arr2.get(i)+" ");
         }
         }
}