# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution(object):
def pathSum(self, root, sum):
"""
:type root: TreeNode
:type sum: int
:rtype: int
"""
self.res = 0
self.helper(root,sum)
return self.res
def dfs(self,root,sum,count,res):
if not root:
return
count += root.val
if count == sum:
self.res += 1
self.dfs(root.left,sum,count,self.res)
self.dfs(root.right,sum,count,self.res)
def helper(self,root,sum):
if not root:
return
self.dfs(root,sum,0,self.res)
self.helper(root.left,sum)
self.helper(root.right,sum)
