Given a binary tree, return all root-to-leaf paths.
Example
Given the following binary tree:
1
/ \
2 3
\
5
All root-to-leaf paths are:
[
"1->2->5",
"1->3"
]
LeetCode上的原题，请参见我之前的博客Binary Tree Paths。
解法一：
class Solution { public: /** * @param root the root of the binary tree * @return all root-to-leaf paths */ vector<string> binaryTreePaths(TreeNode* root) { vector<string> res; if (root) helper(root, "", res); return res; } void helper(TreeNode *node, string out, vector<string> &res) { out += to_string(node->val); if (!node->left && !node->right) { res.push_back(out); } else { if (node->left) helper(node->left, out + "->", res); if (node->right) helper(node->right, out + "->", res); } } };
解法二：
class Solution { public: /** * @param root the root of the binary tree * @return all root-to-leaf paths */ vector<string> binaryTreePaths(TreeNode* root) { if (!root) return {}; if (!root->left && !root->right) return {to_string(root->val)}; vector<string> left = binaryTreePaths(root->left); vector<string> right = binaryTreePaths(root->right); left.insert(left.end(), right.begin(), right.end()); for (auto &a : left) { a = to_string(root->val) + "->" + a; } return left; } };
[LintCode] Binary Tree Paths 二叉树路径
原文：http://www.cnblogs.com/grandyang/p/5562581.html