We have a binary search tree and a number N. Our task is to find the greatest number in the binary search tree that is less than or equal to N. Print the value of the element if it exists otherwise print -1.
Examples:For the above given binary search tree-
Input : N = 24 Output :result = 21 (searching for 24 will be like-5->12->21) Input : N = 4 Output : result = 3 (searching for 4 will be like-5->2->3)
We have discussed recursive approach in below post.
Largest number in BST which is less than or equal to N
Here an iterative approach is discussed. We try to find the predecessor of the target. Keep two pointers, one pointing to the current node and one for storing the answer. If the current node’s data > N, we move towards left. In other case, when current node’s data is less than N, the current node can be our answer (so far), and we move towards right.
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