Description

Submission

/**
 * 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:
    vector<vector<int>> pathSum(TreeNode* root, int sum) {
        vector<vector<int>> res;
        vector<int> card;

        backtrack(root, sum, card, res);

        return res;
    }

private:
    void backtrack(TreeNode* root, int sum, vector<int>& card, vector<vector<int>>& res) {
        if(root == NULL) {
            return;
        }
        if(!root->left && !root->right && sum == root->val) {
            card.push_back(root->val);
            res.push_back(card);
            card.pop_back();
            return;
        }
        card.push_back(root->val);
        backtrack(root->left, sum - root->val, card, res);
        backtrack(root->right, sum - root->val, card, res);
        card.pop_back();
    }
};