How should I practice Minimum Swaps to Group Ones in a Square?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Amazon phone screen problems in FastPrep.

Is Minimum Swaps to Group Ones in a Square associated with Amazon?

FastPrep tags this as a Amazon phone screen coding practice problem when the problem catalog has that company and stage context.

Minimum Swaps to Group Ones in a Square

Amazon● MediumINTERNPHONE SCREEN

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Problem statement

Given a square binary matrix grid, move all its ones into one contiguous, axis-aligned square using as few swaps as possible. There are exactly k * k ones for some positive integer k, so the destination square has side length k.

For this exercise, one swap exchanges the contents of any two cells; the cells need not be adjacent. Return the minimum number of swaps. The input always permits a k x k square within the matrix.

Function

minimumSquareGroupingSwaps(grid: int[][]) → int

Examples

Example 1

grid = [[1,0,0],[1,0,1],[0,1,0]]return = 2

The source example has four ones. The top-left 2 by 2 square already contains two, so two swaps bring the other ones inside.

Example 2

grid = [[1,1,0],[1,1,0],[0,0,0]]return = 0

All four ones already fill a contiguous square.

Example 3

grid = [[1,0,1],[0,0,0],[1,0,1]]return = 3

Every 2 by 2 square contains only one of the four corner ones.

Constraints

1 <= grid.length <= 100; every row has the same length as the number of rows.
Every cell is 0 or 1.
The number of ones is a positive perfect square k * k, with 1 <= k <= grid.length.