"content":"<p>A peak element is an element that is strictly greater than its neighbors.</p>\n\n<p>Given an integer array <code>nums</code>, find a peak element, and return its index. If the array contains multiple peaks, return the index to <strong>any of the peaks</strong>.</p>\n\n<p>You may imagine that <code>nums[-1] = nums[n] = -∞</code>.</p>\n\n<p>You must write an algorithm that runs in <code>O(log n)</code> time.</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> nums = [1,2,3,1]\n<strong>Output:</strong> 2\n<strong>Explanation:</strong> 3 is a peak element and your function should return the index number 2.</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> nums = [1,2,1,3,5,6,4]\n<strong>Output:</strong> 5\n<strong>Explanation:</strong> Your function can return either index number 1 where the peak element is 2, or index number 5 where the peak element is 6.</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= nums.length <= 1000</code></li>\n\t<li><code>-2<sup>31</sup> <= nums[i] <= 2<sup>31</sup> - 1</code></li>\n\t<li><code>nums[i] != nums[i + 1]</code> for all valid <code>i</code>.</li>\n</ul>\n",
"similarQuestions":"[{\"title\": \"Peak Index in a Mountain Array\", \"titleSlug\": \"peak-index-in-a-mountain-array\", \"difficulty\": \"Easy\", \"translatedTitle\": null}, {\"title\": \"Find a Peak Element II\", \"titleSlug\": \"find-a-peak-element-ii\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Pour Water Between Buckets to Make Water Levels Equal\", \"titleSlug\": \"pour-water-between-buckets-to-make-water-levels-equal\", \"difficulty\": \"Medium\", \"translatedTitle\": null}, {\"title\": \"Count Hills and Valleys in an Array\", \"titleSlug\": \"count-hills-and-valleys-in-an-array\", \"difficulty\": \"Easy\", \"translatedTitle\": null}]",
"exampleTestcases":"[1,2,3,1]\n[1,2,1,3,5,6,4]",
"categoryTitle":"Algorithms",
"contributors":[],
"topicTags":[
{
"name":"Array",
"slug":"array",
"translatedName":null,
"__typename":"TopicTagNode"
},
{
"name":"Binary Search",
"slug":"binary-search",
"translatedName":null,
"__typename":"TopicTagNode"
}
],
"companyTagStats":null,
"codeSnippets":[
{
"lang":"C++",
"langSlug":"cpp",
"code":"class Solution {\npublic:\n int findPeakElement(vector<int>& nums) {\n \n }\n};",
"__typename":"CodeSnippetNode"
},
{
"lang":"Java",
"langSlug":"java",
"code":"class Solution {\n public int findPeakElement(int[] nums) {\n \n }\n}",
"envInfo":"{\"cpp\": [\"C++\", \"<p>Compiled with <code> clang 11 </code> using the latest C++ 17 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 gnu99 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://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-9\\\" target=\\\"_blank\\\">C# 10 with .NET 6 runtime</a></p>\\r\\n\\r\\n<p>Your code is compiled with debug flag enabled (<code>/debug</code>).</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 <a href=\\\"https://github.com/datastructures-js/priority-queue\\\" target=\\\"_blank\\\">datastructures-js/priority-queue</a> and <a href=\\\"https:
