257. 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 #
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
}