669. Trim a Binary Search Tree
Given the root
of a binary search tree and the lowest and highest boundaries as low
and high
, trim the tree so that all its elements lies in [low, high]
. Trimming the tree should not change the relative structure of the elements that will remain in the tree (i.e., any node's descendant should remain a descendant). It can be proven that there is a unique answer.
Return the root of the trimmed binary search tree. Note that the root may change depending on the given bounds.
Example 1:
Input: root = [1,0,2], low = 1, high = 2
Output: [1,null,2]
Example 2:
Input: root = [3,0,4,null,2,null,null,1], low = 1, high = 3
Output: [3,2,null,1]
Example 3:
Input: root = [1], low = 1, high = 2
Output: [1]
Example 4:
Input: root = [1,null,2], low = 1, high = 3
Output: [1,null,2]
Example 5:
Input: root = [1,null,2], low = 2, high = 4
Output: [2]
Constraints:
- The number of nodes in the tree in the range
[1, 104]
. 0 <= Node.val <= 104
- The value of each node in the tree is unique.
root
is guaranteed to be a valid binary search tree.0 <= low <= high <= 104
# @lc code=start
using LeetCode
trim_BST(::Nothing, L::Int, R::Int) = nothing
function trim_BST(root::TreeNode{Int}, L::Int, R::Int)
root.val > R && return trim_BST(root.left, L, R)
root.val < L && return trim_BST(root.right, L, R)
root.left = trim_BST(root.left, L, R)
root.right = trim_BST(root.right, L, R)
return root
end
# @lc code=end
trim_BST (generic function with 2 methods)
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