LC-0897 Easy LeetCode

897. Increasing Order Search Tree

Stack Tree Depth-First Search Binary Search Tree Binary Tree

Read the full problem statement on LeetCode.

Difficulty: easy Acceptance: 79% Topics: Stack, Tree, Depth-First Search, Binary Search Tree, Binary Tree

Reading material

Stacks & Queues 11 min Trees & Traversals 18 min

Reference solution (spoiler · python)

# Time:  O(n)
# Space: O(h)

class TreeNode(object):
    def __init__(self, x):
        self.val = x
        self.left = None
        self.right = None


class Solution(object):
    def increasingBST(self, root):
        """
        :type root: TreeNode
        :rtype: TreeNode
        """
        def increasingBSTHelper(root, tail):
            if not root:
                return tail
            result = increasingBSTHelper(root.left, root)
            root.left = None
            root.right = increasingBSTHelper(root.right, tail)
            return result
        return increasingBSTHelper(root, None)

Solution from kamyu104/LeetCode-Solutions · MIT