[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]
]

与上题一样，继续DFS.

 1 /**
 2  * Definition for binary tree
 3  * struct TreeNode {
 4  *     int val;
 5  *     TreeNode *left;
 6  *     TreeNode *right;
 7  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 8  * };
 9  */
10 class Solution {
11 private:
12     vector<vector<int> > ret;
13 public:
14     void dfs(TreeNode *node, int sum, int curSum, vector<int> a)
15     {
16         if (node == NULL)
17             return;
18         
19         if (node->left == NULL && node->right == NULL)
20         {
21             if (curSum + node->val == sum)
22             {
23                 a.push_back(node->val);
24                 ret.push_back(a);
25             }
26             return;
27         }
28         
29         a.push_back(node->val);
30         dfs(node->left, sum, curSum + node->val, a);
31         dfs(node->right, sum, curSum + node->val, a);
32     }
33     
34     vector<vector<int> > pathSum(TreeNode *root, int sum) {
35         // Start typing your C/C++ solution below
36         // DO NOT write int main() function
37         ret.clear();
38         vector<int> a; 
39         dfs(root, sum, 0, a);
40         return ret;
41     }
42 };