Introduction

In this blog post, we will explore how to solve the LeetCode problem "59" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

Given a positive integer n, generate an n x n matrix filled with elements from 1 to n2 in spiral order. Example 1: Input: n = 3 Output: [[1,2,3],[8,9,4],[7,6,5]] Example 2: Input: n = 1 Output: [[1]] Constraints: 1 <= n <= 20

Explanation

Here's the solution to generate an n x n matrix filled with elements from 1 to n^2 in spiral order:

• High-Level Approach:

  • Initialize an n x n matrix with all elements set to 0.
  • Iterate through the matrix in a spiral manner, filling in the numbers from 1 to n^2. The spiral traversal can be simulated by defining boundaries (top, bottom, left, right) and moving within these boundaries.
  • Update the boundaries as the spiral progresses.

• Complexity:

  • Runtime Complexity: O(n^2)
  • Storage Complexity: O(n^2)

Code

    def generateMatrix(n: int) -> list[list[int]]:
    """
    Generates an n x n matrix filled with elements from 1 to n^2 in spiral order.
    """

    matrix = [[0] * n for _ in range(n)]
    num = 1
    top, bottom = 0, n - 1
    left, right = 0, n - 1
    direction = 0  # 0: right, 1: down, 2: left, 3: up

    while top <= bottom and left <= right:
        if direction == 0:  # right
            for i in range(left, right + 1):
                matrix[top][i] = num
                num += 1
            top += 1
        elif direction == 1:  # down
            for i in range(top, bottom + 1):
                matrix[i][right] = num
                num += 1
            right -= 1
        elif direction == 2:  # left
            for i in range(right, left - 1, -1):
                matrix[bottom][i] = num
                num += 1
            bottom -= 1
        elif direction == 3:  # up
            for i in range(bottom, top - 1, -1):
                matrix[i][left] = num
                num += 1
            left += 1

        direction = (direction + 1) % 4

    return matrix