二叉树的路径和

给定一个二叉树，找出所有路径中各节点相加总和等于给定 目标值 的路径。

一个有效的路径，指的是从根节点到叶节点的路径。

样例

给定一个二叉树，和 目标值 = 5:

     1
    / \
   2   4
  / \
 2   3

返回：

[
  [1, 2, 2],
  [1, 4]
]

/**
 * Definition of TreeNode:
 * class TreeNode {
 * public:
 *     int val;
 *     TreeNode *left, *right;
 *     TreeNode(int val) {
 *         this->val = val;
 *         this->left = this->right = NULL;
 *     }
 * }
 */

vector<TreeNode*> t;
 vector<int> k;
class Solution {
public:
    /*
     * @param root: the root of binary tree
     * @param target: An integer
     * @return: all valid paths
     */
    vector<vector<int>> binaryTreePathSum(TreeNode* root,int target) {
       vector<vector<int> > kk;
        if(root == NULL)
           return kk;
        binaryTreeSum_target(root,kk,target);
        return kk;
        
    }
   
    void binaryTreeSum_target(TreeNode* root,vector<vector<int>> &path,int target)
    {
        
        if(root != NULL )
        {
            t.push_back(root);
            if(root->left == NULL && root->right == NULL)
            {
                int s = 0;
                for(int i=0;i<t.size();i++)
                {
                    TreeNode* node = NULL;
                    node = t[i];
                    s += node->val;
                    k.push_back(node->val);
                   // t.pop();
                }
                if(s == target)
                {
                    path.push_back(k);
                }
                k.clear();
                t.pop_back();
                return ;
            }
            binaryTreeSum_target(root->left,path,target);
            binaryTreeSum_target(root->right,path,target);
            t.pop_back();
        }
    }
};