题目：257. 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”]
题意：#
难度不大，考察树的遍历
解法：#
C++版本实现方法：
/**
* 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> results;
visitTreeNode(root, "", results);
return results;
}
private:
void visitTreeNode(TreeNode* node, string path, vector<string>& result)
{
if(node == nullptr) return;
if (!path.empty())
{
path += "->";
}
path += int2Str(node->val);
if (node->left == nullptr && node->right == nullptr)
{
result.push_back(path);
}
else
{
if (node->left != nullptr)
{
visitTreeNode(node->left, path, result);
}
if (node->right != nullptr)
{
visitTreeNode(node->right, path, result);
}
}
}
std::string int2Str(int nValue)
{
ostringstream ss;
ss << nValue;
return ss.str();
}
}