[LeetCode] Binary Tree Paths
Given a binary tree, return all root-to-leaf paths.
For example, given the following binary tree:
1 / \ 2 3 \ 5
All root-to-leaf paths are:
["1->2->5", "1->3"]
输出一个树的路径。使用递归的方法
/** * 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<string> binaryTreePaths(TreeNode* root) { vector<string> res; if (root == nullptr) return res; binaryTreePathsCore(res, root, to_string(root->val)); return res; } void binaryTreePathsCore(vector<string>& res, TreeNode* root, string s) { if (root->left == nullptr && root->right == nullptr) { res.push_back(s); return; } if (root->left != nullptr) binaryTreePathsCore(res, root->left, s + "->" + to_string(root->left->val)); if (root->right != nullptr) binaryTreePathsCore(res, root->right, s + "->" + to_string(root->right->val)); } }; // 6 ms