# ---
# title: 437. Path Sum III
# id: problem437
# author: Tian Jun
# date: 2020-10-31
# difficulty: Medium
# categories: Tree
# link: <https://leetcode.com/problems/path-sum-iii/description/>
# hidden: true
# ---
# 
# You are given a binary tree in which each node contains an integer value.
# 
# Find the number of paths that sum to a given value.
# 
# The path does not need to start or end at the root or a leaf, but it must go
# downwards (traveling only from parent nodes to child nodes).
# 
# The tree has no more than 1,000 nodes and the values are in the range
# -1,000,000 to 1,000,000.
# 
# **Example:**
# 
#     
#     
#     root = [10,5,-3,3,2,null,11,3,-2,null,1], sum = 8
#     
#           10
#          /  \
#         **5**   **-3**
#        **/** **\**    **\**
#       **3**   **2**   **11**
#      / \   **\**
#     3  -2   **1**
#     
#     Return 3. The paths that sum to 8 are:
#     
#     1.  5 -> 3
#     2.  5 -> 2 -> 1
#     3. -3 -> 11
#     
# 
# 
## @lc code=start
using LeetCode

## add your code here:
## @lc code=end
