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257. 二叉树的所有路径-leetcode

Table of Contents

• 1. 题目
• 2. 代码
• 3 ad0 . 思路

1 题目

257. 二叉树的所有路径

2 代码

/**
* Definition for a binary tree node.
* class TreeNode {
*     public $val = null;
*     public $left = null;
*     public $right = null;
*     function __construct($value) { $this->val = $value; }
* }
*/
class Solution {
private $ret = [];

/**
* @param TreeNode $root
* @return String[]
*/
function binaryTreePaths($root) {
$this->ret = [];

if (empty($root)) {
return $this->ret;
}
$path = $root->val;
$this->dfs($root, $path, 1);

return $this->ret;
}

function dfs($root, $path, $isRoot = 0) {
if (! $isRoot) {
$path = $path."->".$root->val;
}
if (empty($root->left) && empty($root->right)) {
$this->ret[] = strval($path);
}
if ($root->left) {
$this->dfs($root->left, $path);
}
if ($root->right) {
$this->dfs($root->right, $path);
}
}
}

3 思路

深度优先遍历，或者广度优先遍历都可以

我这里加了一个函数的变量 isRoot，有点冗余，可以通过优化去掉

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作者: 吴丹阳 https://www.cnblogs.com/wudanyang

更新时间: 2020-09-01 Tue 13:35

Emacs 27.1 (Org mode 9.3.7)

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天行健，君子以自强不息。

地势坤，君子以厚德载物。

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