Two elements of a binary search tree (BST) are swapped by mistake.
Tell us the 2 values swapping which the tree will be restored.
A solution using O(n) space is pretty straight forward. Could you devise a constant space solution?
Input : 1 / \ 2 3 Output : [1, 2] Explanation : Swapping 1 and 2 will change the BST to be 2 / \ 1 3 which is a valid BST