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]
]

代码如下：

/**
* Definition for a binary tree node.
* 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) {
vector<vector<int>> result;
vector<int> temp;
pathSum(result,temp,root,sum);
return result;
}

void pathSum(vector<vector<int>>& result,vector<int>& temp,TreeNode* root,int sum)
{
if(root == NULL) return;
if(root->left == NULL && root->right == NULL && root->val == sum)
{
temp.push_back(root->val);
result.push_back(temp);
temp.pop_back();
return;
}
temp.push_back(root->val);
pathSum(result,temp,root->left,sum-root->val);
pathSum(result,temp,root->right,sum-root->val);
temp.pop_back();

}
};