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题目:
https://leetcode-cn.com/problems/path-sum-ii/comments/
题意:
给定一个二叉树和一个目标和,找到所有从根节点到叶子节点路径总和等于给定目标和的路径。
说明: 叶子节点是指没有子节点的节点。
思路:
递归搜索时记录路径
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>> ans;
vector<int> temp;
work(root, sum, temp, ans);
return ans;
}
void work(TreeNode* root, int sum, vector<int>&temp, vector<vector<int>>&ans) {
if(root == nullptr) {
return;
}
if(!root->left && !root->right && sum - root->val == 0) {
temp.emplace_back(root->val);
ans.emplace_back(temp);
temp.pop_back();
return;
}
temp.emplace_back(root->val);
work(root->left, sum - root->val, temp, ans);
work(root->right, sum - root->val, temp, ans);
temp.pop_back();
}
};