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]]
分析:典型DFS。
/**
* 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 {
private:
vector<vector<int>> ret;
public:
vector<vector<int>> pathSum(TreeNode* root, int sum) {
if(root==NULL)
return ret;
vector<int> temp;
dfs(root,sum,temp);
return ret;
}
void dfs(TreeNode* root,int sum,vector<int> temp){
temp.push_back(root->val);
if(root->val==sum&&root->right==NULL&&root->left==NULL)
ret.push_back(temp);
if(root->left)
dfs(root->left,sum-(root->val),temp);
if(root->right)
dfs(root->right,sum-(root->val),temp);
}
};