leetcode 37：path-sum-ii

题目描述

给定一个二叉树和一个值

返回
[
[5,4,11,2],
[5,8,9]
]

题目分析：这道题和leetcode 22：sum-root-to-leaf-numbers解法基本一致。

代码如下：

 1 void GetPathSum(TreeNode* root,vector<vector<int>> &ret,vector<int> &tmp,int &retSum,int sum)
 2     {
 3         if(root == NULL)
 4             return;
 5         
 6         tmp.push_back(root->val);
 7         retSum += root->val;
 8         if(!root->left&& !root->right) //子节点
 9         {
10             if(sum == retSum)
11                 ret.push_back(tmp);
12         }
13         else{
14             if(root->left)
15                 GetPathSum(root->left,ret,tmp,retSum,sum);
16             if(root->right)
17                 GetPathSum(root->right,ret,tmp,retSum,sum);
18         }
19         retSum -= root->val;
20         tmp.pop_back();
21     }
22     vector<vector<int> > pathSum(TreeNode* root, int sum) {
23         vector<vector<int>> ret;
24         vector<int> tmp;
25         int retSum = 0;
26         GetPathSum(root,ret,tmp,retSum,sum);
27         return ret;
28     }