Java programming question

[Hindhustani]

 

public class BinaryTree_2 {

    Node root;

    boolean hasPathSum(Node node, int sum)
    {
        boolean ans = false;

        int subSum = sum - node.data;
        if(subSum == 0 && node.left == null && node.right == null){

            System.out.println("subSum ******* "+subSum);
            return true;

        }

        if(node.left != null) {

            System.out.println("Left ******* "+node.left.data);
            ans = ans || hasPathSum(node.left, subSum);
        }

        if(node.right != null) {

            // But if it is true then we can avoid calling hasPathSum
            // here as answer has already been found

            System.out.println(
                    "Right ******* "+node.right.data
            );

           ans = ans || hasPathSum(node.right, subSum);

        }
        return(ans);
    }

    // Driver Code
    public static void main(String args[])
    {
        int sum = 21;

        /* Constructed binary tree is
              10
             /  \
           8     2
          / \   /
         3   5 2
        */
        BinaryTree_2 tree = new BinaryTree_2();
        tree.root = new Node(10);
        tree.root.left = new Node(8);
        tree.root.right = new Node(6);
        tree.root.left.left = new Node(3);
        tree.root.left.right = new Node(5);
        tree.root.right.left = new Node(2);

        if (tree.hasPathSum(tree.root, sum))
            System.out.println(
                    "There is a root to leaf path with sum "
                            + sum);
        else
            System.out.println(
                    "There is no root to leaf path with sum "
                            + sum);
    }
}

 

 

output: 

 

Left ******* 8
Left ******* 3
subSum ******* 0 ——> ####at this line why method is not returning but still executing below if condition?####
Right ******* 5
Right ******* 6
There is a root to leaf path with sum 21

[ysshakeela]

1 hour ago, Hindhustani said:

 

public class BinaryTree_2 {

    Node root;

    boolean hasPathSum(Node node, int sum)
    {
        boolean ans = false;

        int subSum = sum - node.data;
        if(subSum == 0 && node.left == null && node.right == null){

            System.out.println("subSum ******* "+subSum);
            return true;

        }

        if(node.left != null) {

            System.out.println("Left ******* "+node.left.data);
            ans = ans || hasPathSum(node.left, subSum);
        }

        if(node.right != null) {

            // But if it is true then we can avoid calling hasPathSum
            // here as answer has already been found

            System.out.println(
                    "Right ******* "+node.right.data
            );

           ans = ans || hasPathSum(node.right, subSum);

        }
        return(ans);
    }

    // Driver Code
    public static void main(String args[])
    {
        int sum = 21;

        /* Constructed binary tree is
              10
             /  \
           8     2
          / \   /
         3   5 2
        */
        BinaryTree_2 tree = new BinaryTree_2();
        tree.root = new Node(10);
        tree.root.left = new Node(8);
        tree.root.right = new Node(6);
        tree.root.left.left = new Node(3);
        tree.root.left.right = new Node(5);
        tree.root.right.left = new Node(2);

        if (tree.hasPathSum(tree.root, sum))
            System.out.println(
                    "There is a root to leaf path with sum "
                            + sum);
        else
            System.out.println(
                    "There is no root to leaf path with sum "
                            + sum);
    }
}

 

 

output: 

 

Left ******* 8
Left ******* 3
subSum ******* 0 ——> ####at this line why method is not returning but still executing below if condition?####
Right ******* 5
Right ******* 6
There is a root to leaf path with sum 21

Where is the class definition of Node baa?

[ysshakeela]

Ok I can interpret like this

public class Node {

    Node(int data) {
        this.data = data;
    }

    Node left;

    Node right;

    int data = 0;

}

[Gowtham7777]

 some unfinished function call are executed. 

like after return hasPathSum is finished from its previous call. 

 

ex: ans = ans || hasPathSum(node.left, subSum); 

once its returns true this continues next line   if(node.right != null) {

[ysshakeela]

1 hour ago, Hindhustani said:

 

public class BinaryTree_2 {

    Node root;

    boolean hasPathSum(Node node, int sum)
    {
        boolean ans = false;

        int subSum = sum - node.data;
        if(subSum == 0 && node.left == null && node.right == null){

            System.out.println("subSum ******* "+subSum);
            return true;

        }

        if(node.left != null) {

            System.out.println("Left ******* "+node.left.data);
            ans = ans || hasPathSum(node.left, subSum);
        }

       else  if(node.right != null) {

            // But if it is true then we can avoid calling hasPathSum
            // here as answer has already been found

            System.out.println(
                    "Right ******* "+node.right.data
            );

           ans = ans || hasPathSum(node.right, subSum);

        }
        return(ans);
    }

    // Driver Code
    public static void main(String args[])
    {
        int sum = 21;

        /* Constructed binary tree is
              10
             /  \
           8     2
          / \   /
         3   5 2
        */
        BinaryTree_2 tree = new BinaryTree_2();
        tree.root = new Node(10);
        tree.root.left = new Node(8);
        tree.root.right = new Node(6);
        tree.root.left.left = new Node(3);
        tree.root.left.right = new Node(5);
        tree.root.right.left = new Node(2);

        if (tree.hasPathSum(tree.root, sum))
            System.out.println(
                    "There is a root to leaf path with sum "
                            + sum);
        else
            System.out.println(
                    "There is no root to leaf path with sum "
                            + sum);
    }
}

 

 

output: 

 

Left ******* 8
Left ******* 3
subSum ******* 0 ——> ####at this line why method is not returning but still executing below if condition?####
Right ******* 5
Right ******* 6
There is a root to leaf path with sum 21

Add this:

"else  if(node.right != null) {"

instead of " if(node.right != null) {"

inside the method hasPathSum(..)

[Hindhustani]

15 minutes ago, Gowtham7777 said:

 some unfinished function call are executed. 

like after return hasPathSum is finished from its previous call. 

 

ex: ans = ans || hasPathSum(node.left, subSum); 

once its returns true this continues next line   if(node.right != null) {

Bro , my understanding is that it should return and exit from method when there is a return statement condition met .. first time I’m seeing the scenario like this  .. can you help me to explain more 

 

@Gowtham7777

[Gowtham7777]

2 minutes ago, Hindhustani said:

Bro , my understanding is that it should return and exit from method when there is a return statement condition met .. first time I’m seeing the scenario like this  .. can you help me to explain more 

 

@Gowtham7777

you are missing this :  hasPathSum function is calling itself... 

like hasPathSum -> hasPathSum 

so if return true, second func is done, first one is continuing its execution 

 

if you still didn't get it let me know... google for function recursion examples...

[Hindhustani]

19 minutes ago, ysshakeela said:

Add this:

"else  if(node.right != null) {"

instead of " if(node.right != null) {"

inside the method hasPathSum(..)

Thanks bro but even with if statement when the return condition satisfies why it is not returns?

[quickgun_murugun]

1 hour ago, Hindhustani said:

 

public class BinaryTree_2 {

    Node root;

    boolean hasPathSum(Node node, int sum)
    {
        boolean ans = false;

        int subSum = sum - node.data;
        if(subSum == 0 && node.left == null && node.right == null){

            System.out.println("subSum ******* "+subSum);
            return true;

        }

        if(node.left != null) {

            System.out.println("Left ******* "+node.left.data);
            ans = ans || hasPathSum(node.left, subSum);
        }

        if(node.right != null) {

            // But if it is true then we can avoid calling hasPathSum
            // here as answer has already been found

            System.out.println(
                    "Right ******* "+node.right.data
            );

           ans = ans || hasPathSum(node.right, subSum);

        }
        return(ans);
    }

    // Driver Code
    public static void main(String args[])
    {
        int sum = 21;

        /* Constructed binary tree is
              10
             /  \
           8     2
          / \   /
         3   5 2
        */
        BinaryTree_2 tree = new BinaryTree_2();
        tree.root = new Node(10);
        tree.root.left = new Node(8);
        tree.root.right = new Node(6);
        tree.root.left.left = new Node(3);
        tree.root.left.right = new Node(5);
        tree.root.right.left = new Node(2);

        if (tree.hasPathSum(tree.root, sum))
            System.out.println(
                    "There is a root to leaf path with sum "
                            + sum);
        else
            System.out.println(
                    "There is no root to leaf path with sum "
                            + sum);
    }
}

 

 

output: 

 

Left ******* 8
Left ******* 3
subSum ******* 0 ——> ####at this line why method is not returning but still executing below if condition?####
Right ******* 5
Right ******* 6
There is a root to leaf path with sum 21

Cool

[Hindhustani]

5 minutes ago, Gowtham7777 said:

you are missing this :  hasPathSum function is calling itself... 

like hasPathSum -> hasPathSum 

so if return true, second func is done, first one is continuing its execution 

 

if you still didn't get it let me know... google for function recursion examples...

Thank you bro, I got it .. how much exp you have in Java? It’s been years I did coding trying to brush skills .. 

[Gowtham7777]

10 minutes ago, Hindhustani said:

Thank you bro, I got it .. how much exp you have in Java? It’s been years I did coding trying to brush skills .. 

this is not java concept, this is programming stuff... 

 

from my experience I never used recursions in live projects... mostly for interviews only.....

 

coming to java, If you looking for job in java they are lot of other things you need to focus....