"content":"<p>You are given the <code>root</code> of a binary tree with <strong>unique values</strong>.</p>\n\n<p>In one operation, you can choose any two nodes <strong>at the same level</strong> and swap their values.</p>\n\n<p>Return <em>the minimum number of operations needed to make the values at each level sorted in a <strong>strictly increasing order</strong></em>.</p>\n\n<p>The <strong>level</strong> of a node is the number of edges along the path between it and the root node<em>.</em></p>\n\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n<img src=\"https://assets.leetcode.com/uploads/2022/09/18/image-20220918174006-2.png\" style=\"width: 500px; height: 324px;\" />\n<pre>\n<strong>Input:</strong> root = [1,4,3,7,6,8,5,null,null,null,null,9,null,10]\n<strong>Output:</strong> 3\n<strong>Explanation:</strong>\n- Swap 4 and 3. The 2<sup>nd</sup> level becomes [3,4].\n- Swap 7 and 5. The 3<sup>rd</sup> level becomes [5,6,8,7].\n- Swap 8 and 7. The 3<sup>rd</sup> level becomes [5,6,7,8].\nWe used 3 operations so return 3.\nIt can be proven that 3 is the minimum number of operations needed.\n</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n<img src=\"https://assets.leetcode.com/uploads/2022/09/18/image-20220918174026-3.png\" style=\"width: 400px; height: 303px;\" />\n<pre>\n<strong>Input:</strong> root = [1,3,2,7,6,5,4]\n<strong>Output:</strong> 3\n<strong>Explanation:</strong>\n- Swap 3 and 2. The 2<sup>nd</sup> level becomes [2,3].\n- Swap 7 and 4. The 3<sup>rd</sup> level becomes [4,6,5,7].\n- Swap 6 and 5. The 3<sup>rd</sup> level becomes [4,5,6,7].\nWe used 3 operations so return 3.\nIt can be proven that 3 is the minimum number of operations needed.\n</pre>\n\n<p><strong class=\"example\">Example 3:</strong></p>\n<img src=\"https://assets.leetcode.com/uploads/2022/09/18/image-20220918174052-4.png\" style=\"width: 400px; height: 274px;\" />\n<pre>\n<strong>Input:</strong> root = [1,2,3,4,5,6]\n<strong>Output:</strong> 0\n<strong>Explanation:</strong> Each level is already sorted in increasing order so return 0.\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li>The number of nodes in the tree is in the range <code>[1, 10<sup>5</sup>]</code>.</li>\n\t<li><code>1 <= Node.val <= 10<sup>5</sup></code></li>\n\t<li>All the values of the tree are <strong>unique</strong>.</li>\n</ul>\n",
"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 MinimumOperations(TreeNode root) {\n \n }\n}",
"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 minimumOperations(root: TreeNode?): Int {\n \n }\n}",
"code":"/**\n * Definition for a binary tree node.\n * type TreeNode struct {\n * Val int\n * Left *TreeNode\n * Right *TreeNode\n * }\n */\nfunc minimumOperations(root *TreeNode) int {\n \n}",
"We can group the values level by level and solve each group independently.",
"Do BFS to group the value level by level.",
"Find the minimum number of swaps to sort the array of each level.",
"While iterating over the array, check the current element, and if not in the correct index, replace that element with the index of the element which should have come."
"envInfo":"{\"cpp\": [\"C++\", \"<p>Compiled with <code> clang 11 </code> using the latest C++ 20 standard.</p>\\r\\n\\r\\n<p>Your code is compiled with level two optimization (<code>-O2</code>). <a href=\\\"https://github.com/google/sanitizers/wiki/AddressSanitizer\\\" target=\\\"_blank\\\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\"], \"java\": [\"Java\", \"<p><code>OpenJDK 17</code>. Java 8 features such as lambda expressions and stream API can be used. </p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\\r\\n<p>Includes <code>Pair</code> class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.</p>\"], \"python\": [\"Python\", \"<p><code>Python 2.7.12</code>.</p>\\r\\n\\r\\n<p>Most libraries are already imported automatically for your convenience, such as <a href=\\\"https://docs.python.org/2/library/array.html\\\" target=\\\"_blank\\\">array</a>, <a href=\\\"https://docs.python.org/2/library/bisect.html\\\" target=\\\"_blank\\\">bisect</a>, <a href=\\\"https://docs.python.org/2/library/collections.html\\\" target=\\\"_blank\\\">collections</a>. If you need more libraries, you can import it yourself.</p>\\r\\n\\r\\n<p>For Map/TreeMap data structure, you may use <a href=\\\"http://www.grantjenks.com/docs/sortedcontainers/\\\" target=\\\"_blank\\\">sortedcontainers</a> library.</p>\\r\\n\\r\\n<p>Note that Python 2.7 <a href=\\\"https://www.python.org/dev/peps/pep-0373/\\\" target=\\\"_blank\\\">will not be maintained past 2020</a>. For the latest Python, please choose Python3 instead.</p>\"], \"c\": [\"C\", \"<p>Compiled with <code>gcc 8.2</code> using the gnu11 standard.</p>\\r\\n\\r\\n<p>Your code is compiled with level one optimization (<code>-O1</code>). <a href=\\\"https://github.com/google/sanitizers/wiki/AddressSanitizer\\\" target=\\\"_blank\\\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\\r\\n\\r\\n<p>Most standard library headers are already included automatically for your convenience.</p>\\r\\n\\r\\n<p>For hash table operations, you may use <a href=\\\"https://troydhanson.github.io/uthash/\\\" target=\\\"_blank\\\">uthash</a>. \\\"uthash.h\\\" is included by default. Below are some examples:</p>\\r\\n\\r\\n<p><b>1. Adding an item to a hash.</b>\\r\\n<pre>\\r\\nstruct hash_entry {\\r\\n int id; /* we'll use this field as the key */\\r\\n char name[10];\\r\\n UT_hash_handle hh; /* makes this structure hashable */\\r\\n};\\r\\n\\r\\nstruct hash_entry *users = NULL;\\r\\n\\r\\nvoid add_user(struct hash_entry *s) {\\r\\n HASH_ADD_INT(users, id, s);\\r\\n}\\r\\n</pre>\\r\\n</p>\\r\\n\\r\\n<p><b>2. Looking up an item in a hash:</b>\\r\\n<pre>\\r\\nstruct hash_entry *find_user(int user_id) {\\r\\n struct hash_entry *s;\\r\\n HASH_FIND_INT(users, &user_id, s);\\r\\n return s;\\r\\n}\\r\\n</pre>\\r\\n</p>\\r\\n\\r\\n<p><b>3. Deleting an item in a hash:</b>\\r\\n<pre>\\r\\nvoid delete_user(struct hash_entry *user) {\\r\\n HASH_DEL(users, user); \\r\\n}\\r\\n</pre>\\r\\n</p>\"], \"csharp\": [\"C#\", \"<p><a href=\\\"https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-10\\\" target=\\\"_blank\\\">C# 10 with .NET 6 runtime</a></p>\"], \"javascript\": [\"JavaScript\", \"<p><code>Node.js 16.13.2</code>.</p>\\r\\n\\r\\n<p>Your code is run with <code>--harmony</code> flag, enabling <a href=\\\"http://node.green/\\\" target=\\\"_blank\\\">new ES6 features</a>.</p>\\r\\n\\r\\n<p><a href=\\\"https://lodash.com\\\" target=\\\"_blank\\\">lodash.js</a> library is included by default.</p>\\r\\n\\r\\n<p>For Priority Queue / Queue data structures, you may use 5.3.0 version of <a href=\\\"https://github.com/datastructures-js/priority-queue/tree/fb4fdb984834421279aeb081df7af624d17c2a03\\\" target=\\\"_blank\\\">datastructures-js/priority-queue</a> and 4.2.1 version of <a href=\\\"https://githu
