1902. Depth of BST Given Insertion Order π
Description
You are given a 0-indexed integer array order
of length n
, a permutation of integers from 1
to n
representing the order of insertion into a binary search tree.
A binary search tree is defined as follows:
- The left subtree of a node contains only nodes with keys less than the node's key.
- The right subtree of a node contains only nodes with keys greater than the node's key.
- Both the left and right subtrees must also be binary search trees.
The binary search tree is constructed as follows:
order[0]
will be the root of the binary search tree.- All subsequent elements are inserted as the child of any existing node such that the binary search tree properties hold.
Return the depth of the binary search tree.
A binary tree's depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Example 1:
Input: order = [2,1,4,3] Output: 3 Explanation: The binary search tree has a depth of 3 with path 2->3->4.
Example 2:
Input: order = [2,1,3,4] Output: 3 Explanation: The binary search tree has a depth of 3 with path 2->3->4.
Example 3:
Input: order = [1,2,3,4] Output: 4 Explanation: The binary search tree has a depth of 4 with path 1->2->3->4.
Constraints:
n == order.length
1 <= n <= 105
order
is a permutation of integers between1
andn
.
Solutions
Solution 1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 |
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 |
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