题目链接:https://www.acwing.com/problem/content/description/45/
题目如下:
/**
* 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>> result;//记录要返回的答案
vector<int> path;//记录满足条件的一条路径
vector<vector<int>> findPath(TreeNode* root, int sum) {
dfs(root,0,sum);
return result;
}
void dfs(TreeNode* root,int sum,int target){
if(root==NULL) return ;
path.push_back(root->val);//先把当前的点存下来
sum+=root->val;
if(root->left==NULL&&root->right==NULL){
//当前节点为叶子节点,则将路径放入result中
if(sum==target) result.push_back(path);//如果是叶子节点但是不满足target的条件,则不放入,继续走,直到删除,回退回去
}else {
//当前节点不是叶子节点
if(root->left) dfs(root->left,sum,target);
if(root->right) dfs(root->right,sum,target);
}
path.pop_back();//把当前的点删掉,即恢复现场,方便走其他路径
}
};