{ "data": { "question": { "questionId": "1628", "questionFrontendId": "1504", "boundTopicId": null, "title": "Count Submatrices With All Ones", "titleSlug": "count-submatrices-with-all-ones", "content": "

Given an m x n binary matrix mat, return the number of submatrices that have all ones.

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Example 1:

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\nInput: mat = [[1,0,1],[1,1,0],[1,1,0]]\nOutput: 13\nExplanation: \nThere are 6 rectangles of side 1x1.\nThere are 2 rectangles of side 1x2.\nThere are 3 rectangles of side 2x1.\nThere is 1 rectangle of side 2x2. \nThere is 1 rectangle of side 3x1.\nTotal number of rectangles = 6 + 2 + 3 + 1 + 1 = 13.\n
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Example 2:

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\nInput: mat = [[0,1,1,0],[0,1,1,1],[1,1,1,0]]\nOutput: 24\nExplanation: \nThere are 8 rectangles of side 1x1.\nThere are 5 rectangles of side 1x2.\nThere are 2 rectangles of side 1x3. \nThere are 4 rectangles of side 2x1.\nThere are 2 rectangles of side 2x2. \nThere are 2 rectangles of side 3x1. \nThere is 1 rectangle of side 3x2. \nTotal number of rectangles = 8 + 5 + 2 + 4 + 2 + 2 + 1 = 24.\n
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Constraints:

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