leetcode-problemset/leetcode-cn/originData/tree-node.json

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        "question": {
            "questionId": "608",
            "questionFrontendId": "608",
            "categoryTitle": "Database",
            "boundTopicId": 2637,
            "title": "Tree Node",
            "titleSlug": "tree-node",
            "content": "<p>Table: <code>Tree</code></p>\n\n<pre>\n+-------------+------+\n| Column Name | Type |\n+-------------+------+\n| id          | int  |\n| p_id        | int  |\n+-------------+------+\nid is the primary key column for this table.\nEach row of this table contains information about the id of a node and the id of its parent node in a tree.\nThe given structure is always a valid tree.\n</pre>\n\n<p>&nbsp;</p>\n\n<p>Each node in the tree can be one of three types:</p>\n\n<ul>\n\t<li><strong>&quot;Leaf&quot;</strong>: if the node is a leaf node.</li>\n\t<li><strong>&quot;Root&quot;</strong>: if the node is the root of the tree.</li>\n\t<li><strong>&quot;Inner&quot;</strong>: If the node is neither a leaf node nor a root node.</li>\n</ul>\n\n<p>Write an SQL query to report the type of each node in the tree.</p>\n\n<p>Return the result table <strong>ordered</strong> by <code>id</code> <strong>in ascending order</strong>.</p>\n\n<p>The query result format is in the following example.</p>\n\n<p>&nbsp;</p>\n<p><strong>Example 1:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2021/10/22/tree1.jpg\" style=\"width: 304px; height: 224px;\" />\n<pre>\n<strong>Input:</strong> \nTree table:\n+----+------+\n| id | p_id |\n+----+------+\n| 1  | null |\n| 2  | 1    |\n| 3  | 1    |\n| 4  | 2    |\n| 5  | 2    |\n+----+------+\n<strong>Output:</strong> \n+----+-------+\n| id | type  |\n+----+-------+\n| 1  | Root  |\n| 2  | Inner |\n| 3  | Leaf  |\n| 4  | Leaf  |\n| 5  | Leaf  |\n+----+-------+\n<strong>Explanation:</strong> \nNode 1 is the root node because its parent node is null and it has child nodes 2 and 3.\nNode 2 is an inner node because it has parent node 1 and child node 4 and 5.\nNodes 3, 4, and 5 are leaf nodes because they have parent nodes and they do not have child nodes.\n</pre>\n\n<p><strong>Example 2:</strong></p>\n<img alt=\"\" src=\"https://assets.leetcode.com/uploads/2021/10/22/tree2.jpg\" style=\"width: 64px; height: 65px;\" />\n<pre>\n<strong>Input:</strong> \nTree table:\n+----+------+\n| id | p_id |\n+----+------+\n| 1  | null |\n+----+------+\n<strong>Output:</strong> \n+----+-------+\n| id | type  |\n+----+-------+\n| 1  | Root  |\n+----+-------+\n<strong>Explanation:</strong> If there is only one node on the tree, you only need to output its root attributes.\n</pre>\n",
            "translatedTitle": "树节点",
            "translatedContent": "<p>给定一个表&nbsp;<code>tree</code>，<strong>id</strong> 是树节点的编号，&nbsp;<strong>p_id</strong>&nbsp;是它父节点的&nbsp;<strong>id 。</strong></p>\n\n<pre>+----+------+\n| id | p_id |\n+----+------+\n| 1  | null |\n| 2  | 1    |\n| 3  | 1    |\n| 4  | 2    |\n| 5  | 2    |\n+----+------+</pre>\n\n<p>树中每个节点属于以下三种类型之一：</p>\n\n<ul>\n\t<li>叶子：如果这个节点没有任何孩子节点。</li>\n\t<li>根：如果这个节点是整棵树的根，即没有父节点。</li>\n\t<li>内部节点：如果这个节点既不是叶子节点也不是根节点。</li>\n</ul>\n\n<p>&nbsp;</p>\n\n<p>写一个查询语句，输出所有节点的编号和节点的类型，并将结果按照节点编号排序。上面样例的结果为：</p>\n\n<p>&nbsp;</p>\n\n<pre>+----+------+\n| id | Type |\n+----+------+\n| 1  | Root |\n| 2  | Inner|\n| 3  | Leaf |\n| 4  | Leaf |\n| 5  | Leaf |\n+----+------+\n</pre>\n\n<p>&nbsp;</p>\n\n<p><strong>解释</strong></p>\n\n<ul>\n\t<li>节点 &#39;1&#39; 是根节点，因为它的父节点是 NULL ，同时它有孩子节点 &#39;2&#39; 和 &#39;3&#39; 。</li>\n\t<li>节点 &#39;2&#39; 是内部节点，因为它有父节点 &#39;1&#39; ，也有孩子节点 &#39;4&#39; 和 &#39;5&#39; 。</li>\n\t<li>节点 &#39;3&#39;, &#39;4&#39; 和 &#39;5&#39; 都是叶子节点，因为它们都有父节点同时没有孩子节点。</li>\n\t<li>样例中树的形态如下：\n\t<p>&nbsp;</p>\n\n\t<pre>\t\t\t  1\n\t\t\t/   \\\n                      2       3\n                    /   \\\n                  4       5\n</pre>\n\n\t<p>&nbsp;</p>\n\t</li>\n</ul>\n\n<p><strong>注意</strong></p>\n\n<p>如果树中只有一个节点，你只需要输出它的根属性。</p>\n",
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            "difficulty": "Medium",
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            "topicTags": [
                {
                    "name": "Database",
                    "slug": "database",
                    "translatedName": "数据库",
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                {
                    "lang": "MySQL",
                    "langSlug": "mysql",
                    "code": "# Write your MySQL query statement below",
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                {
                    "lang": "MS SQL Server",
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                    "code": "/* Write your T-SQL query statement below */",
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                    "lang": "Oracle",
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                    "code": "/* Write your PL/SQL query statement below */",
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            "hints": [
                "You can judge the node type by querying whether the node's id shows up in p_id column and whether the node's p_id is null."
            ],
            "solution": null,
            "status": null,
            "sampleTestCase": "{\"headers\": {\"Tree\": [\"id\", \"p_id\"]}, \"rows\": {\"Tree\": [[1,null],[2,1],[3,1],[4,2],[5,2]]}}",
            "metaData": "{\n  \"mysql\": [\n    \"Create table If Not Exists Tree (id int, p_id int)\"\n  ],\n  \"mssql\": [\n    \"Create table Tree (id int, p_id int)\"\n  ],\n  \"oraclesql\": [\n    \"Create table Tree (id int, p_id int)\"\n  ],\n  \"database\": true\n}",
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            "judgeType": "large",
            "mysqlSchemas": [
                "Create table If Not Exists Tree (id int, p_id int)",
                "Truncate table Tree",
                "insert into Tree (id, p_id) values ('1', 'None')",
                "insert into Tree (id, p_id) values ('2', '1')",
                "insert into Tree (id, p_id) values ('3', '1')",
                "insert into Tree (id, p_id) values ('4', '2')",
                "insert into Tree (id, p_id) values ('5', '2')"
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            "style": "LEETCODE",
            "exampleTestcases": "{\"headers\": {\"Tree\": [\"id\", \"p_id\"]}, \"rows\": {\"Tree\": [[1,null],[2,1],[3,1],[4,2],[5,2]]}}\n{\"headers\": {\"Tree\": [\"id\", \"p_id\"]}, \"rows\": {\"Tree\": [[1,null]]}}",
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