Package g0101_0200.s0114_flatten_binary_tree_to_linked_list

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    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)?

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Unit flatten(TreeNode root)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait