480. 二叉树的所有路径
给一棵二叉树,找出从根节点到叶子节点的所有路径。
样例
给出下面这棵二叉树:
1
/ \
2 3
\
5
所有根到叶子的路径为:
[
"1->2->5",
"1->3"
]
解题思路:
递归。
/**
* Definition of TreeNode:
* class TreeNode {
* public:
* int val;
* TreeNode *left, *right;
* TreeNode(int val) {
* this->val = val;
* this->left = this->right = NULL;
* }
* }
*/
class Solution {
public:
/**
* @param root: the root of the binary tree
* @return: all root-to-leaf paths
*/
vector<string> binaryTreePaths(TreeNode * root)
{
// write your code here
vector<string> res;
if(root == NULL)
return res;
if(root->left == NULL && root->right == NULL) //叶子节点
{
res.push_back(to_string(root->val));
return res;
}
vector<string> leftS = binaryTreePaths(root->left);
for(int i=0;i<leftS.size();i++)
res.push_back(to_string(root->val) + "->" + leftS[i]);
vector<string> rightS = binaryTreePaths(root->right);
for(int i=0;i<rightS.size();i++)
res.push_back(to_string(root->val) + "->" + rightS[i]);
return res;
}
};