count-good-nodes-in-binary-tree.json

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            "title": "Count Good Nodes in Binary Tree",
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            "content": "<p>Given a binary tree <code>root</code>, a node <em>X</em> in the tree is named&nbsp;<strong>good</strong> if in the path from root to <em>X</em> there are no nodes with a value <em>greater than</em> X.</p>\r\n\r\n<p>Return the number of <strong>good</strong> nodes in the binary tree.</p>\r\n\r\n<p>&nbsp;</p>\r\n<p><strong class=\"example\">Example 1:</strong></p>\r\n\r\n<p><strong><img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/04/02/test_sample_1.png\" style=\"width: 263px; height: 156px;\" /></strong></p>\r\n\r\n<pre>\r\n<strong>Input:</strong> root = [3,1,4,3,null,1,5]\r\n<strong>Output:</strong> 4\r\n<strong>Explanation:</strong> Nodes in blue are <strong>good</strong>.\r\nRoot Node (3) is always a good node.\r\nNode 4 -&gt; (3,4) is the maximum value in the path starting from the root.\r\nNode 5 -&gt; (3,4,5) is the maximum value in the path\r\nNode 3 -&gt; (3,1,3) is the maximum value in the path.</pre>\r\n\r\n<p><strong class=\"example\">Example 2:</strong></p>\r\n\r\n<p><strong><img alt=\"\" src=\"https://assets.leetcode.com/uploads/2020/04/02/test_sample_2.png\" style=\"width: 157px; height: 161px;\" /></strong></p>\r\n\r\n<pre>\r\n<strong>Input:</strong> root = [3,3,null,4,2]\r\n<strong>Output:</strong> 3\r\n<strong>Explanation:</strong> Node 2 -&gt; (3, 3, 2) is not good, because &quot;3&quot; is higher than it.</pre>\r\n\r\n<p><strong class=\"example\">Example 3:</strong></p>\r\n\r\n<pre>\r\n<strong>Input:</strong> root = [1]\r\n<strong>Output:</strong> 1\r\n<strong>Explanation:</strong> Root is considered as <strong>good</strong>.</pre>\r\n\r\n<p>&nbsp;</p>\r\n<p><strong>Constraints:</strong></p>\r\n\r\n<ul>\r\n\t<li>The number of nodes in the binary tree is in the range&nbsp;<code>[1, 10^5]</code>.</li>\r\n\t<li>Each node&#39;s value is between <code>[-10^4, 10^4]</code>.</li>\r\n</ul>",
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                    "name": "Tree",
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                    "name": "Depth-First Search",
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                    "name": "Binary Tree",
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                    "lang": "C++",
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                    "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n *     int val;\n *     TreeNode *left;\n *     TreeNode *right;\n *     TreeNode() : val(0), left(nullptr), right(nullptr) {}\n *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}\n *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}\n * };\n */\nclass Solution {\npublic:\n    int goodNodes(TreeNode* root) {\n        \n    }\n};",
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                    "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n *     int val;\n *     TreeNode left;\n *     TreeNode right;\n *     TreeNode() {}\n *     TreeNode(int val) { this.val = val; }\n *     TreeNode(int val, TreeNode left, TreeNode right) {\n *         this.val = val;\n *         this.left = left;\n *         this.right = right;\n *     }\n * }\n */\nclass Solution {\n    public int goodNodes(TreeNode root) {\n        \n    }\n}",
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                    "lang": "Python",
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                    "code": "# Definition for a binary tree node.\n# class TreeNode(object):\n#     def __init__(self, val=0, left=None, right=None):\n#         self.val = val\n#         self.left = left\n#         self.right = right\nclass Solution(object):\n    def goodNodes(self, root):\n        \"\"\"\n        :type root: TreeNode\n        :rtype: int\n        \"\"\"\n        ",
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                    "code": "# Definition for a binary tree node.\n# class TreeNode:\n#     def __init__(self, val=0, left=None, right=None):\n#         self.val = val\n#         self.left = left\n#         self.right = right\nclass Solution:\n    def goodNodes(self, root: TreeNode) -> int:\n        ",
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                    "code": "/**\n * Definition for a binary tree node.\n * struct TreeNode {\n *     int val;\n *     struct TreeNode *left;\n *     struct TreeNode *right;\n * };\n */\n\n\nint goodNodes(struct TreeNode* root){\n\n}",
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                    "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n *     public int val;\n *     public TreeNode left;\n *     public TreeNode right;\n *     public TreeNode(int val=0, TreeNode left=null, TreeNode right=null) {\n *         this.val = val;\n *         this.left = left;\n *         this.right = right;\n *     }\n * }\n */\npublic class Solution {\n    public int GoodNodes(TreeNode root) {\n        \n    }\n}",
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                    "code": "/**\n * Definition for a binary tree node.\n * function TreeNode(val, left, right) {\n *     this.val = (val===undefined ? 0 : val)\n *     this.left = (left===undefined ? null : left)\n *     this.right = (right===undefined ? null : right)\n * }\n */\n/**\n * @param {TreeNode} root\n * @return {number}\n */\nvar goodNodes = function(root) {\n    \n};",
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                    "code": "/**\n * Definition for a binary tree node.\n * class TreeNode {\n *     val: number\n *     left: TreeNode | null\n *     right: TreeNode | null\n *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {\n *         this.val = (val===undefined ? 0 : val)\n *         this.left = (left===undefined ? null : left)\n *         this.right = (right===undefined ? null : right)\n *     }\n * }\n */\n\nfunction goodNodes(root: TreeNode | null): number {\n\n};",
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                    "code": "/**\n * Definition for a binary tree node.\n * class TreeNode {\n *     public $val = null;\n *     public $left = null;\n *     public $right = null;\n *     function __construct($val = 0, $left = null, $right = null) {\n *         $this->val = $val;\n *         $this->left = $left;\n *         $this->right = $right;\n *     }\n * }\n */\nclass Solution {\n\n    /**\n     * @param TreeNode $root\n     * @return Integer\n     */\n    function goodNodes($root) {\n        \n    }\n}",
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                    "code": "/**\n * Definition for a binary tree node.\n * public class TreeNode {\n *     public var val: Int\n *     public var left: TreeNode?\n *     public var right: TreeNode?\n *     public init() { self.val = 0; self.left = nil; self.right = nil; }\n *     public init(_ val: Int) { self.val = val; self.left = nil; self.right = nil; }\n *     public init(_ val: Int, _ left: TreeNode?, _ right: TreeNode?) {\n *         self.val = val\n *         self.left = left\n *         self.right = right\n *     }\n * }\n */\nclass Solution {\n    func goodNodes(_ root: TreeNode?) -> Int {\n        \n    }\n}",
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                    "lang": "Kotlin",
                    "langSlug": "kotlin",
                    "code": "/**\n * Example:\n * var ti = TreeNode(5)\n * var v = ti.`val`\n * Definition for a binary tree node.\n * class TreeNode(var `val`: Int) {\n *     var left: TreeNode? = null\n *     var right: TreeNode? = null\n * }\n */\nclass Solution {\n    fun goodNodes(root: TreeNode?): Int {\n        \n    }\n}",
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                    "lang": "Go",
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                    "code": "/**\n * Definition for a binary tree node.\n * type TreeNode struct {\n *     Val int\n *     Left *TreeNode\n *     Right *TreeNode\n * }\n */\nfunc goodNodes(root *TreeNode) int {\n    \n}",
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                    "code": "# Definition for a binary tree node.\n# class TreeNode\n#     attr_accessor :val, :left, :right\n#     def initialize(val = 0, left = nil, right = nil)\n#         @val = val\n#         @left = left\n#         @right = right\n#     end\n# end\n# @param {TreeNode} root\n# @return {Integer}\ndef good_nodes(root)\n    \nend",
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                    "code": "/**\n * Definition for a binary tree node.\n * class TreeNode(_value: Int = 0, _left: TreeNode = null, _right: TreeNode = null) {\n *   var value: Int = _value\n *   var left: TreeNode = _left\n *   var right: TreeNode = _right\n * }\n */\nobject Solution {\n    def goodNodes(root: TreeNode): Int = {\n        \n    }\n}",
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                    "code": "// Definition for a binary tree node.\n// #[derive(Debug, PartialEq, Eq)]\n// pub struct TreeNode {\n//   pub val: i32,\n//   pub left: Option<Rc<RefCell<TreeNode>>>,\n//   pub right: Option<Rc<RefCell<TreeNode>>>,\n// }\n// \n// impl TreeNode {\n//   #[inline]\n//   pub fn new(val: i32) -> Self {\n//     TreeNode {\n//       val,\n//       left: None,\n//       right: None\n//     }\n//   }\n// }\nuse std::rc::Rc;\nuse std::cell::RefCell;\nimpl Solution {\n    pub fn good_nodes(root: Option<Rc<RefCell<TreeNode>>>) -> i32 {\n        \n    }\n}",
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                "Use DFS (Depth First Search) to traverse the tree, and constantly keep track of the current path maximum."
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