# Binary Tree Path Sum

## Problem

Given a binary tree, find all paths that sum of the nodes in the path equals to a given number target.

A valid path is from root node to any of the leaf nodes.

## Example

Given a binary tree, and target = 5:

     1
/ \
2   4
/ \
2   3

return

[
[1, 2, 2],
[1, 4]
]

## Code - Java

/**
* Definition of TreeNode:
* public class TreeNode {
*   public int val;
*   public TreeNode left, right;
*   public TreeNode(int val) {
*     this.val = val;
*     this.left = this.right = null;
*   }
* }
*/
public class Solution {
/**
* @param root   the root of binary tree
* @param target an integer
* @return all valid paths
*/
public List<List<Integer>> binaryTreePathSum(TreeNode root, int target) {
List<List<Integer>> result = new ArrayList<>();

if (root == null) return result;
search(result, buffer, root, target);
return result;
}

private void search(List<List<Integer>> result, LinkedList<Integer> buffer, TreeNode node, int target) {
if (node.left == null && node.right == null) {
int sum = 0;
for (int i : buffer) {
sum += i;
}
if (sum == target) {
}
return;
}

if (node.left != null) {

}