# [257. Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/)


## 题目

Given a binary tree, return all root-to-leaf paths.

**Note**: A leaf is a node with no children.

**Example**:

    Input:
    
       1
     /   \
    2     3
     \
      5
    
    Output: ["1->2->5", "1->3"]
    
    Explanation: All root-to-leaf paths are: 1->2->5, 1->3

## 题目大意

给定一个二叉树，返回所有从根节点到叶子节点的路径。说明: 叶子节点是指没有子节点的节点。

## 解题思路

- Google 的面试题，考察递归



## 代码

```go

package leetcode

import (
	"strconv"
)

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func binaryTreePaths(root *TreeNode) []string {
	if root == nil {
		return []string{}
	}
	res := []string{}
	if root.Left == nil && root.Right == nil {
		return []string{strconv.Itoa(root.Val)}
	}
	tmpLeft := binaryTreePaths(root.Left)
	for i := 0; i < len(tmpLeft); i++ {
		res = append(res, strconv.Itoa(root.Val)+"->"+tmpLeft[i])
	}
	tmpRight := binaryTreePaths(root.Right)
	for i := 0; i < len(tmpRight); i++ {
		res = append(res, strconv.Itoa(root.Val)+"->"+tmpRight[i])
	}
	return res
}

```