Root.java

/* This program is to find value of root node in a tree 
when value of each node and sum of child nodes of all nodes is given. */

package javacodes;    //encapsulates a group of classes into a package called javacodes

import java.util.*;     //import package of util class

public class Root {

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

        System.out.println("Number of vertices in tree");

        int v = in.nextInt();     //taking number of vertices as input

        int sumt = 0, sumc = 0, tmp;

        System.out.println("Values of vertices");

        for (int i = 1; i <= v; i++) {
            tmp = in.nextInt();       //taking values of each node as input

            sumt += tmp;
        }

        System.out.println("Enter sum of child's values");

        for (int i = 1; i <= v; i++) {
            tmp = in.nextInt();

            sumc += tmp;
        }

        System.out.println("Value of root node is :" + (sumt - sumc));
    }
}