How to convert a binary tree to binary search tree in-place, i.e., we cannot use any extra space

Question

How to convert a binary tree to binary search tree in-place, i.e., we cannot use any extra space.

Answer 1

A binary tree usually is a binary search tree, in which case no conversion is required.

Perhaps you need to clarify the structure of what you are converting from. Is your source tree unbalanced? Is it not ordered by the key you want to search on? How did you arrive at the source tree?