{ "data": { "question": { "questionId": "978", "questionFrontendId": "941", "boundTopicId": null, "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.

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

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Example 1:

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

Example 2:

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

Example 3:

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

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Most standard library headers are already included automatically for your convenience.

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OpenJDK 17 . Java 8 features such as lambda expressions and stream API can be used.

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Python 2.7.12.

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C# 10 with .NET 6 runtime

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Ruby 3.1

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Go 1.17.6.

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Python 3.10.

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