题解 | #二叉树中和为某一值的路径(一)#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @param sum int整型 
# @return bool布尔型
#
class Solution:
    def hasPathSum(self , root: TreeNode, sum: int) -> bool:
        # write code here
        return self.dfs(root, 0, sum)

    def dfs(self, root: TreeNode, value: int, sum:int):
        if root:
            value += root.val
        else:
            return False
        if value == sum and not root.left and not root.right:
            return True
        else:
            res1 = self.dfs(root.left, value, sum)
            if res1:
                return True
            else:
                return self.dfs(root.right, value, sum)