Class Solution


  • public class Solution
    extends Object
    114 - Flatten Binary Tree to Linked List.

    Medium

    Given the root of a binary tree, flatten the tree into a “linked list”:

    • The “linked list” should use the same TreeNode class where the right child pointer points to the next node in the list and the left child pointer is always null.
    • The “linked list” should be in the same order as a pre-order traversal of the binary tree.

    Example 1:

    Input: root = [1,2,5,3,4,null,6]

    Output: [1,null,2,null,3,null,4,null,5,null,6]

    Example 2:

    Input: root = []

    Output: []

    Example 3:

    Input: root = [0]

    Output: [0]

    Constraints:

    • The number of nodes in the tree is in the range [0, 2000].
    • -100 <= Node.val <= 100

    Follow up: Can you flatten the tree in-place (with O(1) extra space)?

    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • flatten

        public void flatten​(TreeNode root)