leetcode-113. 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]
]

题意：找出所有和为指定sum的路径链。（112升级版）

思路：君可曾记得引用传参result？（这不就搞定了吗！哈哈哈）

Accepted Code：
 1 /**
 2  * Definition for a binary tree node.
 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     vector<vector<int>> pathSum(TreeNode* root, int sum) {
13         vector<vector<int>> result;
14         vector<int> tempResult;
15         pathSum(root,sum,result,tempResult);
16         return result;
17     }
18     
19     void pathSum(TreeNode* root,int sum,vector<vector<int>>& result,vector<int>& tempResult)
20     {
21         if(root==nullptr)
22         return;
23         tempResult.push_back(root->val);
24         if(root->left==nullptr&&root->right==nullptr&&sum==root->val){
25             result.push_back(vector<int>(tempResult));
26             tempResult.erase(tempResult.end()-1);
27             return;
28         }else
29         {
30             pathSum(root->left,sum-root->val,result,tempResult);
31             pathSum(root->right,sum-root->val,result,tempResult);
32         }
33         tempResult.erase(tempResult.end()-1);
34     }
35 };

 

posted @ 2017-02-20 21:23  Pacific-hong  阅读(141)  评论(0)  编辑  收藏  举报