[LeetCode]merge two binary trees (완료)

[yeonghwanjeon]

• 문제링크
• 나의 풀이
  • Traverse와 관련된 문제인 듯
  • 우선 Preorder / Recursive 방식으로 품 -> O(n)
  • Iterative하게 풀어볼 것
  • 참고링크
  • DFS를 iterative하게 푸는 경우, Stack을 이용
  • BFS를 iterative하게 푸는 경우, Queue를 이용
  • Traverse 방식 다시 볼 것

    
    # Definition for a binary tree node.
    # class TreeNode(object):
    #     def __init__(self, x):
    #         self.val = x
    #         self.left = None
    #         self.right = None

class Solution(object): def mergeTrees(self, t1, t2): """ :type t1: TreeNode :type t2: TreeNode :rtype: TreeNode """ if t1 == None : return t2

    if t2 == None :
        return t1

    t = TreeNode(t1.val + t2.val)
    t.left = self.mergeTrees(t1.left, t2.left)
    t.right = self.mergeTrees(t1.right, t2.right)

    return t

[yeonghwanjeon]

• 다른 풀이

  class Solution(object):
  def mergeTrees(self, t1, t2):
      """
      :type t1: TreeNode
      :type t2: TreeNode
      :rtype: TreeNode
      """
      if t1 and t2:
          t1.val += t2.val
          t1.left = self.mergeTrees(t1.left, t2.left)
          t1.right = self.mergeTrees(t1.right, t2.right)
          return t1
      else:
          return t1 or t2