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Solution: The K Weakest Rows in a Matrix

Discover how to efficiently find the k weakest rows in a binary matrix by combining binary search with a max-heap. This lesson helps you understand counting soldiers in rows, managing ties, and optimizing selection using advanced data structures within time and space constraints.

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Statement

You are given an m×nm \times n binary matrix of 11’s (representing soldiers) and 00’s (representing civilians). The soldiers are positioned in front of the civilians, i.e., all the 11’s will appear to the left of all the 00’s in each row.

A row ii is weaker than a row jj if any of the following is TRUE:

  • The number of soldiers in row ii is less than the number of soldiers in row jj.

  • Both rows have the same number of soldiers and  ...