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Path Sum II

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Description

https://leetcode.com/problems/path-sum-ii/description/

Solution

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/**
 * 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>> ret;
        int curSum = 0;
        vector<int> curVector;
        check(curSum, sum, ret, root,curVector);
        return ret;
    }
    void check(int curSum, int sum, vector<vector<int>>& ret, TreeNode* root, vector<int>& curVector) {
        if (root == NULL) return;
        curSum += root->val;
        curVector.push_back(root->val);
        if (!root->left && !root->right && sum == curSum) ret.push_back(vector<int>(curVector));

        check(curSum, sum, ret, root->left, curVector);
        check(curSum, sum, ret, root->right, curVector);  
        
        curVector.pop_back();
        return;
    }
};