"content":"<p>Given an array <code>nums</code> of <code>n</code> integers where <code>nums[i]</code> is in the range <code>[1, n]</code>, return <em>an array of all the integers in the range</em> <code>[1, n]</code> <em>that do not appear in</em> <code>nums</code>.</p>\n\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n<pre><strong>Input:</strong> nums = [4,3,2,7,8,2,3,1]\n<strong>Output:</strong> [5,6]\n</pre><p><strong class=\"example\">Example 2:</strong></p>\n<pre><strong>Input:</strong> nums = [1,1]\n<strong>Output:</strong> [2]\n</pre>\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>n == nums.length</code></li>\n\t<li><code>1 <= n <= 10<sup>5</sup></code></li>\n\t<li><code>1 <= nums[i] <= n</code></li>\n</ul>\n\n<p> </p>\n<p><strong>Follow up:</strong> Could you do it without extra space and in <code>O(n)</code> runtime? You may assume the returned list does not count as extra space.</p>\n",
"similarQuestions":"[{\"title\": \"First Missing Positive\", \"titleSlug\": \"first-missing-positive\", \"difficulty\": \"Hard\", \"translatedTitle\": null}, {\"title\": \"Find All Duplicates in an Array\", \"titleSlug\": \"find-all-duplicates-in-an-array\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Find Unique Binary String\", \"titleSlug\": \"find-unique-binary-string\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Append K Integers With Minimal Sum\", \"titleSlug\": \"append-k-integers-with-minimal-sum\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Replace Elements in an Array\", \"titleSlug\": \"replace-elements-in-an-array\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Maximum Number of Integers to Choose From a Range I\", \"titleSlug\": \"maximum-number-of-integers-to-choose-from-a-range-i\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Maximum Number of Integers to Choose From a Range II\", \"titleSlug\": \"maximum-number-of-integers-to-choose-from-a-range-ii\", \"difficulty\": \"Medium\", \"translatedTitle\": null}]",
"code":"/**\n * Note: The returned array must be malloced, assume caller calls free().\n */\nint* findDisappearedNumbers(int* nums, int numsSize, int* returnSize) {\n \n}",
"This is a really easy problem if you decide to use additional memory. For those trying to write an initial solution using additional memory, think <b>counters!</b>",
"However, the trick really is to not use any additional space than what is already available to use. Sometimes, multiple passes over the input array help find the solution. However, there's an interesting piece of information in this problem that makes it easy to re-use the input array itself for the solution.",
"The problem specifies that the numbers in the array will be in the range [1, n] where n is the number of elements in the array. Can we use this information and modify the array in-place somehow to find what we need?"
"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
