Introduction

In this blog post, we will explore how to solve the LeetCode problem "118" 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 an integer numRows, return the first numRows of Pascal's triangle. In Pascal's triangle, each number is the sum of the two numbers directly above it as shown: Example 1: Input: numRows = 5 Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]] Example 2: Input: numRows = 1 Output: [[1]] Constraints: 1 <= numRows <= 30

Explanation

• Iterative Construction: Build the triangle row by row. Each row is generated using the values from the previous row.
  • Calculate Intermediate Values: For each row, the intermediate values (excluding the first and last element which are always 1) are the sum of the two elements directly above in the previous row.

• Runtime Complexity: O(numRows²), Storage Complexity: O(numRows²)

Code

    def generate(numRows: int) -> list[list[int]]:
    """
    Generates Pascal's triangle up to numRows.

    Args:
        numRows: The number of rows to generate.

    Returns:
        A list of lists representing Pascal's triangle.
    """
    triangle = []
    for i in range(numRows):
        row = [1] * (i + 1)
        if i > 1:
            for j in range(1, i):
                row[j] = triangle[i - 1][j - 1] + triangle[i - 1][j]
        triangle.append(row)
    return triangle