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]]
分析: dfs求解即可
/**
* 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:
void find(TreeNode* root, int sum,vector<int>& curPath, vector<vector<int>> & res ){
if(root==nullptr)
return;
if(root->left){
curPath.push_back(root->left->val);
find(root->left, sum-root->val, curPath,res);
curPath.pop_back();
}
if(root->right){
curPath.push_back(root->right->val);
find(root->right, sum-root->val,curPath,res);
curPath.pop_back();
}
if(root->left==nullptr && root->right==nullptr && sum==root->val)
res.push_back(curPath); return;
}
vector<vector<int>> pathSum(TreeNode* root, int sum) {
vector<vector<int>> res;
if(root==nullptr)
return res;
vector<int> curPath;
curPath.push_back(root->val);
find(root, sum, curPath, res); return res;
}
};