# [112. Path Sum](https://leetcode.com/problems/path-sum/)


## 题目

Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.

**Note:** A leaf is a node with no children.

**Example:**

Given the below binary tree and `sum = 22`,

          5
         / \
        4   8
       /   / \
      11  13  4
     /  \      \
    7    2      1

return true, as there exist a root-to-leaf path `5->4->11->2` which sum is 22.

## 题目大意

给定一个二叉树和一个目标和，判断该树中是否存在根节点到叶子节点的路径，这条路径上所有节点值相加等于目标和。说明: 叶子节点是指没有子节点的节点。


## 解题思路

- 递归求解即可