#0292

Spiral Matrix Order

MediumDSA28 min20 XP

Problem

Given a matrix, return its values in clockwise spiral order starting from the top-left corner.

Why This Matters

Spiral traversal trains careful boundary updates, a common source of off-by-one bugs.

Function Signature

def spiral_order(matrix):

Examples

Example 1

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

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

Walk top row, right column, bottom row reversed, left column reversed, then move inward.

Constraints

Return the exact requested value.
Handle edge cases cleanly.
Use the intended DSA pattern when brute force would scale poorly.

CodePython

def spiral_order(matrix):
    """
    Input example: matrix = [[1,2,3],[4,5,6],[7,8,9]]
    Return: [1, 2, 3, 6, 9, 8, 7, 4, 5]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

def spiral_order(matrix):
    """
    Input example: matrix = [[1,2,3],[4,5,6],[7,8,9]]
    Return: [1, 2, 3, 6, 9, 8, 7, 4, 5]
    Return the value from the function so the tests can compare it. Do not print unless the prompt asks.
    """
    # write your code here
    return []

Visible browser tests run here when available.

Testcases2 visible / 3 hidden categories

Square matrix

Input3 by 3

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

The center is visited last.

Rectangle matrix

Input3 by 4

Expected[1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7]

Boundary checks avoid revisiting rows or columns.

Hidden Test Categories

single rowsingle columnempty matrix