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]
]

/**
 * Definition for binary tree
 * 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) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<vector<int> > ret;
        vector<int> temp;
        dfs(ret,root,sum,temp);
        return ret;
    }
    
    void dfs(vector<vector<int>> &ret,TreeNode *root,int sum,vector<int> temp)
    {
        if(root == NULL) return;
        if(root->left == NULL && root->right == NULL) 
        {
            if(sum == root->val){
                temp.push_back(root->val);
                ret.push_back(temp); 
            }
            return;
        }
        temp.push_back(root->val);
        dfs(ret,root->left,sum - root->val,temp);
        dfs(ret,root->right,sum - root->val,temp);
    }
};

100 milli secs