#0218

Spiral Number Matrix

HardPython35 min25 XP

Problem

Return an n by n spiral number pattern as a list of integer rows.

Why This Matters

Spiral problems test boundary management, a common source of off-by-one errors in matrix code.

Function Signature

def spiral_matrix(n):

Examples

Example 1

Inputn = 3

Output[[1, 2, 3], [8, 9, 4], [7, 6, 5]]

The numbers move right, down, left, and up while the boundaries shrink.

Constraints

Return the exact requested value.
Handle small edge cases cleanly.
Prefer readable Python over clever shortcuts.

CodePython

def spiral_matrix(n):
    """
    Input example: n = 3
    Return: [[1, 2, 3], [8, 9, 4], [7, 6, 5]]
    For pattern problems, return a list of rows. Do not print the rows.
    """
    # write your code here
    return []

def spiral_matrix(n):
    """
    Input example: n = 3
    Return: [[1, 2, 3], [8, 9, 4], [7, 6, 5]]
    For pattern problems, return a list of rows. Do not print the rows.
    """
    # write your code here
    return []

Visible browser tests run here when available.

Testcases1 visible / 3 hidden categories

Core example

Inputn = 3

Expected[[1, 2, 3], [8, 9, 4], [7, 6, 5]]

The numbers move right, down, left, and up while the boundaries shrink.

Hidden Test Categories

n = 1n = 2n = 4