Cacher is the code snippet organizer for pro developers

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    int pathSum(TreeNode* root, int sum) {
        if (root == NULL) return 0;
        return dfs(root, sum) + pathSum(root->left, sum) + pathSum(root->right, sum);
    }
    
    int dfs(TreeNode* node, int sum) {
        int res = 0;
        if (node == NULL) return res;
        if (sum == node->val) res++;
        res += dfs(node->left, sum - node->val);
        res += dfs(node->right, sum - node->val);
        return res;
    }
};