2023-11-21 09:51:21 +0000 UTC

/**
 * 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<string> binaryTreePaths(TreeNode* root) {
        vector<string> ans;
        dfs(*root, ans, "");
        return ans;
    }

    void dfs(TreeNode& root, vector<string> &ans, string path){
        path += (path.size() ? "->" : "") + std::to_string(root.val);
        if(!root.left && !root.right) {
            ans.push_back(path);
            return;
        }
        if(root.left) {
            dfs(*root.left, ans, path);
        }
        if(root.right) {
            dfs(*root.right, ans, path);
        }
    }
};