Q113. Path Sum II
直达:https://leetcode.com/problems/path-sum-ii/description/
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
类似于Q112, 只需要保存一个变量path记录当前遍历到的节点,迭代的遍历到叶节点之后如果满足路径之和等于sum后将路径插入返回结果中即可。
C++代码
/**
* 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>> res;
if(!root) return res;
vector<int> path;
treePath(root, sum, res, path);
return res;
}
private:
void treePath(TreeNode* root, int sum, vector<vector<int>>& res, vector<int> path){
if(!root) return;
path.push_back(root->val);
if(!root->left && !root->right && sum == root->val){
res.push_back(path);
return;
}
treePath(root->left, sum-root->val, res, path);
treePath(root->right, sum-root->val, res, path);
}
};
Last updated
Was this helpful?