Spiral Matrix – Solution & Complexity

top, bottom = 0, n - 1
left, right = 0, n - 1
value = 1

while top <= bottom and left <= right:
    for col in range(left, right + 1):
        matrix[top][col] = value
        value += 1
    top += 1

def generate_spiral_matrix(n: int) -> list[list[int]]:
    n = int(n)
    if n <= 0:
        return []

    matrix = [[0 for _ in range(n)] for _ in range(n)]
    top, bottom = 0, n - 1
    left, right = 0, n - 1
    value = 1

    while top <= bottom and left <= right:
        for col in range(left, right + 1):
            matrix[top][col] = value
            value += 1
        top += 1

        for row in range(top, bottom + 1):
            matrix[row][right] = value
            value += 1
        right -= 1

        if top <= bottom:
            for col in range(right, left - 1, -1):
                matrix[bottom][col] = value
                value += 1
            bottom -= 1

        if left <= right:
            for row in range(bottom, top - 1, -1):
                matrix[row][left] = value
                value += 1
            left += 1

    return matrix