小黑和阿黄一起楼道里运动被宿管告状让导员电话骂了一顿十分委屈的leetcode之旅:404. 左叶子之和

小黑代码

# 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 = right
class Solution:def sumOfLeftLeaves(self, root: Optional[TreeNode]) -> int:# 根结点为空，则跳出if not root:return 0self.sum = 0# 递归函数def dfs(node):# 递归出口if node.left:if not (node.left.left or node.left.right):self.sum += node.left.valelse:   dfs(node.left)if node.right:dfs(node.right)dfs(root)return self.sum

层次遍历

# 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 = right
class Solution:def sumOfLeftLeaves(self, root: Optional[TreeNode]) -> int:# 根结点为空，则跳出if not root:return 0sum_ = 0# 初始化队列q = collections.deque([root])# 声明匿名函数，判断该点是否是叶子结点is_leaf = lambda node:not (node.left or node.right)# 开始进行层次遍历while q:top = q.popleft()if top.left:if is_leaf(top.left):sum_ += top.left.valelse:q.append(top.left)if top.right:q.append(top.right)return sum_

小黑生活

和阿黄的泡面之旅

和阿黄偷偷会面被莫名发现挨批了,这几天打算消停一下了

接到了辅导员的电话，被狠狠骂了一顿

准备继续学习计算机网络