Question

import java.util.Stack;
import java.util.ArrayList;
import java.util.Scanner;

class TreeNode{
int data;
ArrayList<TreeNode> children = new ArrayList<>();
TreeNode parent = null;
  
public TreeNode(int d){
data = d;
}
  
public TreeNode addChild(int d){
TreeNode n = new TreeNode(d);
n.setParent(this);
children.add(n);
return n;
}
  
public ArrayList<TreeNode> getChildren(){
return children;
}
  
public void setParent(TreeNode p){
parent = p;
}
  
public TreeNode getParent(){
return parent;
}
}

class Main {
public static void main(String[] args)
   {
       Scanner scan = new Scanner(System.in);
       int num;
       //Create a tree
       TreeNode root = new TreeNode(scan.nextInt());
TreeNode node1 = root.addChild(scan.nextInt());
TreeNode node11 = node1.addChild(scan.nextInt());
TreeNode node12 = node1.addChild(scan.nextInt());
TreeNode node2 = root.addChild(scan.nextInt());
TreeNode node21 = node2.addChild(scan.nextInt());
TreeNode node22 = node2.addChild(scan.nextInt());
       TreeNode node211 = node21.addChild(scan.nextInt());
       System.out.println(""+sum(root));
   }

   
public static int sum(TreeNode n) {
       //TODO: Find the sum of the elements in the tree rooted in n
       //Example: if the elements in the tree are: 10, 20, 30, 40, 50, the method should return: 150
  
      
   }

}

Answer 1

Code:

import java.util.*;
import java.util.ArrayList;
import java.util.Scanner;

class TreeNode{
int data;
ArrayList<TreeNode> children = new ArrayList<>();
TreeNode parent = null;
  
public TreeNode(int d){
data = d;
}
  
public TreeNode addChild(int d){
TreeNode n = new TreeNode(d);
n.setParent(this);
children.add(n);
return n;
}
  
public ArrayList<TreeNode> getChildren(){
return children;
}
  
public void setParent(TreeNode p){
parent = p;
}
  
public TreeNode getParent(){
return parent;
}
}

class Main {
public static void main(String[] args)
   {
       Scanner scan = new Scanner(System.in);
       int num;
       //Create a tree
       TreeNode root = new TreeNode(scan.nextInt());
TreeNode node1 = root.addChild(scan.nextInt());
TreeNode node11 = node1.addChild(scan.nextInt());
TreeNode node12 = node1.addChild(scan.nextInt());
TreeNode node2 = root.addChild(scan.nextInt());
TreeNode node21 = node2.addChild(scan.nextInt());
TreeNode node22 = node2.addChild(scan.nextInt());
       TreeNode node211 = node21.addChild(scan.nextInt());
       System.out.println(""+sum(root));
   }

   
public static int sum(TreeNode n) {
    int su = 0;
    if(n==null)
      return 0;
    Queue<TreeNode> q = new LinkedList<>(); 
    q.add(n); 
  
    while (!q.isEmpty())  
    { 
        int ni = q.size(); 
  
        // If this node has children 
        while (ni > 0) 
        { 
  
            // Dequeue an item from queue and 
            // add it to variable "sum" 
            TreeNode p = q.peek(); 
            q.remove(); 
            su += p.data; 
  
            // Enqueue all children of the dequeued item 
            for (int i = 0; i < p.children.size(); i++) 
                q.add(p.children.get(i)); 
            ni--; 
        } 
    } 
    return su; 

}
}

Output: