How should I practice Sort Matrix Borders?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Hudson River Trading online assessment problems in FastPrep.

Is Sort Matrix Borders associated with Hudson River Trading?

FastPrep tags this as a Hudson River Trading online assessment coding practice problem when the problem catalog has that company and stage context.

Problem · Array

Sort Matrix Borders

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Hudson River TradingINTERNOA

Problem statement

Given matrix, an n x m rectangular matrix of integers, let's define its 0-border as the union of its leftmost and rightmost columns, as well as its top and bottom rows. A vector's 0-border is the vector itself.

If we were to remove the matrix's 0-border, then the 0-border of the resulting matrix can be defined as the 1-border of the original matrix. We can continue this way to define the 2-border, 3-border, etc, until we reach the center of the matrix.

For each valid k, your task is to sort the elements in each k-border and place them clockwise in ascending order, starting from the top-left corner.

Note: You are not expected to provide the most optimal solution, but a solution with time complexity not worse than O(n * m * (n + m)) will fit within the execution time limit.

Function

solution(matrix: int[][]) → int[][]

Examples

Example 1

matrix = [[9,7,-4,5],[1,6,2,-6],[12,20,2,0]]return = [[-6,-4,0,1],[20,2,6,2],[12,9,7,5]]

For

matrix = [[9, 7, -4, 5],
          [1, 6, 2, -6],
          [12, 20, 2, 0]]

FastPrep-authored deterministic derivation: The source image shows this example input but is cropped before its output. Applying the visible border-sorting rule gives the executable output shown here.

Constraints

FastPrep execution-adapter constraints (not shown in the source image):
matrix is non-empty.
Every row has the same positive length.
Every entry is an integer.