{ "data": { "question": { "questionId": "2826", "questionFrontendId": "2732", "boundTopicId": null, "title": "Find a Good Subset of the Matrix", "titleSlug": "find-a-good-subset-of-the-matrix", "content": "

You are given a 0-indexed m x n binary matrix grid.

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Let us call a non-empty subset of rows good if the sum of each column of the subset is at most half of the length of the subset.

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More formally, if the length of the chosen subset of rows is k, then the sum of each column should be at most floor(k / 2).

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Return an integer array that contains row indices of a good subset sorted in ascending order.

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If there are multiple good subsets, you can return any of them. If there are no good subsets, return an empty array.

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A subset of rows of the matrix grid is any matrix that can be obtained by deleting some (possibly none or all) rows from grid.

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Example 1:

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\nInput: grid = [[0,1,1,0],[0,0,0,1],[1,1,1,1]]\nOutput: [0,1]\nExplanation: We can choose the 0th and 1st rows to create a good subset of rows.\nThe length of the chosen subset is 2.\n- The sum of the 0th column is 0 + 0 = 0, which is at most half of the length of the subset.\n- The sum of the 1st column is 1 + 0 = 1, which is at most half of the length of the subset.\n- The sum of the 2nd column is 1 + 0 = 1, which is at most half of the length of the subset.\n- The sum of the 3rd column is 0 + 1 = 1, which is at most half of the length of the subset.\n
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Example 2:

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\nInput: grid = [[0]]\nOutput: [0]\nExplanation: We can choose the 0th row to create a good subset of rows.\nThe length of the chosen subset is 1.\n- The sum of the 0th column is 0, which is at most half of the length of the subset.\n
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Example 3:

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\nInput: grid = [[1,1,1],[1,1,1]]\nOutput: []\nExplanation: It is impossible to choose any subset of rows to create a good subset.\n
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Constraints:

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