[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。

/**
* Definition for binary tree
* struct TreeNode {
*     int val;
*     TreeNode *left;
*     TreeNode *right;
*     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
void getPath(TreeNode *root, int sum, vector<vector<int> > &res, vector<int> path) {
if (root == NULL) {
return;
}
path.push_back(root->val);
if (root->left == NULL && root->right == NULL) {
if (root->val == sum) {
res.push_back(path);
}
return;
}
getPath(root->left, sum - root->val, res, path);
getPath(root->right, sum - root->val, res, path);
}

vector<vector<int> > pathSum(TreeNode *root, int sum) {
vector<vector<int> > res;
vector<int> path;
getPath(root, sum, res, path);
return res;
}
};