{ "data": { "question": { "questionId": "2508", "questionFrontendId": "2428", "boundTopicId": null, "title": "Maximum Sum of an Hourglass", "titleSlug": "maximum-sum-of-an-hourglass", "content": "

You are given an m x n integer matrix grid.

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We define an hourglass as a part of the matrix with the following form:

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Return the maximum sum of the elements of an hourglass.

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Note that an hourglass cannot be rotated and must be entirely contained within the matrix.

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Example 1:

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\nInput: grid = [[6,2,1,3],[4,2,1,5],[9,2,8,7],[4,1,2,9]]\nOutput: 30\nExplanation: The cells shown above represent the hourglass with the maximum sum: 6 + 2 + 1 + 2 + 9 + 2 + 8 = 30.\n
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Example 2:

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\nInput: grid = [[1,2,3],[4,5,6],[7,8,9]]\nOutput: 35\nExplanation: There is only one hourglass in the matrix, with the sum: 1 + 2 + 3 + 5 + 7 + 8 + 9 = 35.\n
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Constraints:

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