Tree bottom view question

#1

i dont undertsand how input is being taken in this question in level order form…what does -1 stand for please explainn!!

#2

hello,
You have to buildtree with the help of queue. Prateek bhaiya has taught tree building level wise. I would suggest you to watch github repo where prateek bhaiya build a function buildtreelevelwise.

Hope, this would help.
you can refer https://ide.codingblocks.com/s/65868?_ga=2.27498620.1579452958.1561478804-1448590793.1559468415.

#3

If you are still facing a problem, then refer to the below figure

Click on this.