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"title": "Validate Binary Tree Nodes",
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"content": "<p>You have <code>n</code> binary tree nodes numbered from <code>0</code> to <code>n - 1</code> where node <code>i</code> has two children <code>leftChild[i]</code> and <code>rightChild[i]</code>, return <code>true</code> if and only if <strong>all</strong> the given nodes form <strong>exactly one</strong> valid binary tree.</p>\n\n<p>If node <code>i</code> has no left child then <code>leftChild[i]</code> will equal <code>-1</code>, similarly for the right child.</p>\n\n<p>Note that the nodes have no values and that we only use the node numbers in this problem.</p>\n\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2019/08/23/1503_ex1.png\" style=\"width: 195px; height: 287px;\" />\n<pre>\n<strong>Input:</strong> n = 4, leftChild = [1,-1,3,-1], rightChild = [2,-1,-1,-1]\n<strong>Output:</strong> true\n</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2019/08/23/1503_ex2.png\" style=\"width: 183px; height: 272px;\" />\n<pre>\n<strong>Input:</strong> n = 4, leftChild = [1,-1,3,-1], rightChild = [2,3,-1,-1]\n<strong>Output:</strong> false\n</pre>\n\n<p><strong class=\"example\">Example 3:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2019/08/23/1503_ex3.png\" style=\"width: 82px; height: 174px;\" />\n<pre>\n<strong>Input:</strong> n = 2, leftChild = [1,0], rightChild = [-1,-1]\n<strong>Output:</strong> false\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>n == leftChild.length == rightChild.length</code></li>\n\t<li><code>1 <= n <= 10<sup>4</sup></code></li>\n\t<li><code>-1 <= leftChild[i], rightChild[i] <= n - 1</code></li>\n</ul>\n",
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"code": "class Solution {\npublic:\n bool validateBinaryTreeNodes(int n, vector<int>& leftChild, vector<int>& rightChild) {\n \n }\n};",
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"code": "class Solution {\n public boolean validateBinaryTreeNodes(int n, int[] leftChild, int[] rightChild) {\n \n }\n}",
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"code": "class Solution(object):\n def validateBinaryTreeNodes(self, n, leftChild, rightChild):\n \"\"\"\n :type n: int\n :type leftChild: List[int]\n :type rightChild: List[int]\n :rtype: bool\n \"\"\"\n ",
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"code": "bool validateBinaryTreeNodes(int n, int* leftChild, int leftChildSize, int* rightChild, int rightChildSize) {\n \n}",
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"code": "/**\n * @param {number} n\n * @param {number[]} leftChild\n * @param {number[]} rightChild\n * @return {boolean}\n */\nvar validateBinaryTreeNodes = function(n, leftChild, rightChild) {\n \n};",
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"code": "class Solution {\n\n /**\n * @param Integer $n\n * @param Integer[] $leftChild\n * @param Integer[] $rightChild\n * @return Boolean\n */\n function validateBinaryTreeNodes($n, $leftChild, $rightChild) {\n \n }\n}",
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"code": "# @param {Integer} n\n# @param {Integer[]} left_child\n# @param {Integer[]} right_child\n# @return {Boolean}\ndef validate_binary_tree_nodes(n, left_child, right_child)\n \nend",
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"code": "impl Solution {\n pub fn validate_binary_tree_nodes(n: i32, left_child: Vec<i32>, right_child: Vec<i32>) -> bool {\n \n }\n}",
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"lang": "Racket",
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"code": "(define/contract (validate-binary-tree-nodes n leftChild rightChild)\n (-> exact-integer? (listof exact-integer?) (listof exact-integer?) boolean?)\n )",
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"lang": "Erlang",
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"Find the parent of each node.",
"A valid tree must have nodes with only one parent and exactly one node with no parent."
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