/**
* 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
*
*/
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class PathSumIII437 {
public int pathSum(TreeNode root, int sum) {
int[] res = new int[1];
pathSum(root, sum, res, new ArrayList<>());
return res[0];
}
private void pathSum(TreeNode root, int target, int[] res, List