Hey can anyone help me in this binary tree

Question

Why i am not able to create two binary tree
https://code.sololearn.com/cJPNW9uZV1Kt/?ref=app

Answer 1

root1 is null, probably because of line 29-32:

if (idx>=nodes.length||nodes[idx] == -1) {
return null;
}

What is your goal with this condition?
What is the purpose of idx and why does it start with -1?

Please tidy up your code and use proper indentation, because it is very difficult to see the structure of your program this way, especially since you have nested classes.

Answer 2

Tibor Santa
The purpose of if statement is to not print the -1after leaf node
For example. If binary tree is 1,2,-1,-1
Here 2 is a leaf 🍃 node
And that -1 is to start the index from 0 because of i++🤔