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] ]
Code:
/**
* 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 findPath(TreeNode *node, int n, int &sum, vector<int> &buf, vector<vector<int>> &res){
if(!node)
return;
buf.push_back(node->val);
if(!node->left&&!node->right&&node->val+n==sum){
res.push_back(buf);
buf.pop_back();
return;
}
findPath(node->left,node->val+n,sum,buf,res);
findPath(node->right,node->val+n,sum,buf,res);
buf.pop_back();
}
vector<vector<int> > pathSum(TreeNode *root, int sum) {
vector<int> buf;
vector<vector<int>> res;
findPath(root,0,sum,buf,res);
return res;
}
};