Leetcode Path Sum II

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.

For example:
Given the below binary tree and sum = 22,

              5
             / \
            4   8
           /   / \
          11  13  4
         /  \    / \
        7    2  5   1

return

[
   [5,4,11,2],
   [5,8,4,5]
]

---

代码如下：

/**
 * 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>> result;
        vector<int> temp;
        pathSum(result,temp,root,sum);
        return result;
    }
    
    void pathSum(vector<vector<int>>& result,vector<int>& temp,TreeNode* root,int sum)
    {
        if(root == NULL) return;
        if(root->left == NULL && root->right == NULL && root->val == sum)
        {
            temp.push_back(root->val);
            result.push_back(temp);
            temp.pop_back();
            return;
        }
        temp.push_back(root->val);
        pathSum(result,temp,root->left,sum-root->val);
        pathSum(result,temp,root->right,sum-root->val);
        temp.pop_back();
        
    }
};