【二叉树-简单】112. 路径总和

【题目】
【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 visit(self,root,s=0):
        if not root:
            return 0
        root.val+=s
        # print(root.val," s:",s)
        if root.val==self.targetSum and not root.left and not root.right:
            self.ans=True
            return
        self.visit(root.left,root.val) 
        self.visit(root.right,root.val)
    def hasPathSum(self, root: Optional[TreeNode], targetSum: int) -> bool:
        self.ans=False
        self.targetSum=targetSum
        self.visit(root,0)
        return self.ans