{ "data": { "question": { "questionId": "978", "questionFrontendId": "941", "categoryTitle": "Algorithms", "boundTopicId": 2353, "title": "Valid Mountain Array", "titleSlug": "valid-mountain-array", "content": "

Given an array of integers arr, return true if and only if it is a valid mountain array.

\n\n

Recall that arr is a mountain array if and only if:

\n\n\n\n

 

\n

Example 1:

\n
Input: arr = [2,1]\nOutput: false\n

Example 2:

\n
Input: arr = [3,5,5]\nOutput: false\n

Example 3:

\n
Input: arr = [0,3,2,1]\nOutput: true\n
\n

 

\n

Constraints:

\n\n\n", "translatedTitle": "有效的山脉数组", "translatedContent": "

给定一个整数数组 arr，如果它是有效的山脉数组就返回 true，否则返回 false。

\n\n

让我们回顾一下，如果 arr 满足下述条件，那么它是一个山脉数组：

\n\n\n\n

 

\n\n

\"\"

\n\n

 

\n\n

示例 1：

\n\n
\n输入：arr = [2,1]\n输出：false\n
\n\n

示例 2：

\n\n
\n输入：arr = [3,5,5]\n输出：false\n
\n\n

示例 3：

\n\n
\n输入：arr = [0,3,2,1]\n输出：true
\n\n

 

\n\n

提示：

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arr: List[int]) -> bool:\n ", "__typename": "CodeSnippetNode" }, { "lang": "C", "langSlug": "c", "code": "bool validMountainArray(int* arr, int arrSize) {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "C#", "langSlug": "csharp", "code": "public class Solution {\n public bool ValidMountainArray(int[] arr) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "JavaScript", "langSlug": "javascript", "code": "/**\n * @param {number[]} arr\n * @return {boolean}\n */\nvar validMountainArray = function(arr) {\n \n};", "__typename": "CodeSnippetNode" }, { "lang": "TypeScript", "langSlug": "typescript", "code": "function validMountainArray(arr: number[]): boolean {\n \n};", "__typename": "CodeSnippetNode" }, { "lang": "PHP", "langSlug": "php", "code": "class Solution {\n\n /**\n * @param Integer[] $arr\n * @return Boolean\n */\n function validMountainArray($arr) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Swift", "langSlug": "swift", "code": "class Solution {\n func validMountainArray(_ arr: [Int]) -> Bool {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Kotlin", "langSlug": "kotlin", "code": "class Solution {\n fun validMountainArray(arr: IntArray): Boolean {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Dart", "langSlug": "dart", "code": "class Solution {\n bool validMountainArray(List arr) {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Go", "langSlug": "golang", "code": "func validMountainArray(arr []int) bool {\n \n}", "__typename": "CodeSnippetNode" }, { "lang": "Ruby", "langSlug": "ruby", "code": "# @param {Integer[]} arr\n# @return {Boolean}\ndef valid_mountain_array(arr)\n \nend", "__typename": "CodeSnippetNode" }, { "lang": "Scala", "langSlug": "scala", "code": "object Solution {\n def validMountainArray(arr: Array[Int]): Boolean = {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Rust", "langSlug": "rust", "code": "impl Solution {\n pub fn valid_mountain_array(arr: Vec) -> bool {\n \n }\n}", "__typename": "CodeSnippetNode" }, { "lang": "Racket", "langSlug": "racket", "code": "(define/contract (valid-mountain-array arr)\n (-> (listof exact-integer?) boolean?)\n )", "__typename": "CodeSnippetNode" }, { "lang": "Erlang", "langSlug": "erlang", "code": "-spec valid_mountain_array(Arr :: [integer()]) -> boolean().\nvalid_mountain_array(Arr) ->\n .", "__typename": "CodeSnippetNode" }, { "lang": "Elixir", "langSlug": "elixir", "code": "defmodule Solution do\n @spec valid_mountain_array(arr :: [integer]) :: boolean\n def valid_mountain_array(arr) do\n \n end\nend", "__typename": "CodeSnippetNode" }, { "lang": "Cangjie", "langSlug": "cangjie", "code": "class Solution {\n func validMountainArray(arr: Array): Bool {\n\n }\n}", "__typename": "CodeSnippetNode" } ], "stats": "{\"totalAccepted\": \"98.4K\", \"totalSubmission\": \"245.9K\", \"totalAcceptedRaw\": 98427, \"totalSubmissionRaw\": 245900, \"acRate\": \"40.0%\"}", "hints": [ "It's very easy to keep track of a monotonically increasing or decreasing ordering of elements. 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