[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]
]

 

水。

 

 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 public:
12     void getPath(TreeNode *root, int sum, vector<vector<int> > &res, vector<int> path) {
13         if (root == NULL) {
14             return;
15         }
16         path.push_back(root->val);
17         if (root->left == NULL && root->right == NULL) {
18             if (root->val == sum) {
19                 res.push_back(path);
20             }
21             return;
22         }
23         getPath(root->left, sum - root->val, res, path);
24         getPath(root->right, sum - root->val, res, path);
25     }
26     
27     vector<vector<int> > pathSum(TreeNode *root, int sum) {
28         vector<vector<int> > res;
29         vector<int> path;
30         getPath(root, sum, res, path);
31         return res;
32     }
33 };

 

posted @ 2014-03-31 01:16  Eason Liu  阅读(140)  评论(0)  编辑  收藏  举报