hyunkookim 님의 블로그

DFS : 깊이 우선 탐색 BFS: 넓이 우선 탐색   구현 방법방문한 노드는 다시 방문 X모든 노드를 다 탐색https://youtu.be/CUTXL4NFTGE?si=AdqhxDTmJRQfyjPY

129. Sum Root to Leaf Numbers # Definition for a binary tree node.# class TreeNode:# def __init__(self, val=0, left=None, right=None):# self.val = val# self.left = left# self.right = rightclass Solution: def sumNumbers(self, root: Optional[TreeNode]) -> int: stack = [] def dfs(node, curString): if not node: return ..

112. Path Sum # Definition for a binary tree node.# class TreeNode:# def __init__(self, val=0, left=None, right=None):# self.val = val# self.left = left# self.right = rightclass Solution: def hasPathSum(self, root: Optional[TreeNode], targetSum: int) -> bool: # DFS로.. def dfs(node, curSum): if not node: return False ..

114. Flatten Binary Tree to Linked List # Definition for a binary tree node.# class TreeNode:# def __init__(self, val=0, left=None, right=None):# self.val = val# self.left = left# self.right = rightclass Solution: def flatten(self, root: Optional[TreeNode]) -> None: """ Do not return anything, modify root in-place instead. """ # preorder..

117. Populating Next Right Pointers in Each Node II https://youtu.be/68RmOoq-OSs?si=-Ss1BuJuc5nIqS5A """# Definition for a Node.class Node: def __init__(self, val: int = 0, left: 'Node' = None, right: 'Node' = None, next: 'Node' = None): self.val = val self.left = left self.right = right self.next = next"""# 큐로 품class Solution: def connect(self, root: 'Node') ->..

106. Construct Binary Tree from Inorder and Postorder Traversal # Definition for a binary tree node.# class TreeNode:# def __init__(self, val=0, left=None, right=None):# self.val = val# self.left = left# self.right = rightclass Solution: def buildTree(self, inorder: List[int], postorder: List[int]) -> Optional[TreeNode]: # inorder: 왼, 중, 오 # postoder:..