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 Solution
public int pathSum(TreeNode root, int sum) {
if (root == null) {
return 0;
}
return findPath(root, sum) + pathSum(root.left, sum) + pathSum(root.right, sum);
}
private int findPath(TreeNode root, int sum) {
if (root == null) {
return 0;
}
int res = 0;
if (root.val == sum) {
res++;
}
res += findPath(root.left, sum - root.val);
res += findPath(root.right, sum - root.val);
return
