LeetCode 113. 路径总和 II

LeetCode 113. 路径总和 II

思路：

dfs

代码：

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    vector<vector<int>> res;
    vector<int> path;
    vector<vector<int>> pathSum(TreeNode* root, int targetSum) {
        if(!root) return {};
        dfs(root,targetSum);
        return res;
    }

    void dfs(TreeNode* root,int targetSum){
        targetSum-=root->val;
        path.push_back(root->val);
        //找出所有 从根节点到叶子节点 路径总和等于给定目标和的路径。
        if(!root->left && !root->right && !targetSum){
            res.push_back(path);
        } 
        else{
            if(root->left) dfs(root->left,targetSum);
            
            if(root->right) dfs(root->right,targetSum);
            
        }
        path.pop_back();
        
    }
};