Pascal's Triangle Python Solution with Tests

lcpy gen -n 118   # by problem number
lcpy gen -s pascals_triangle   # by problem name

Input: numRows = 5
Output: [[1],[1,1],[1,2,1],[1,3,3,1],[1,4,6,4,1]]

Input: numRows = 1
Output: [[1]]

class Solution:
    # Time: O(n^2)
    # Space: O(1) excluding output
    def generate(self, num_rows: int) -> list[list[int]]:
        triangle: list[list[int]] = [[1]]
        for _ in range(1, num_rows):
            previous = triangle[-1]
            row = [1] + [previous[i] + previous[i + 1] for i in range(len(previous) - 1)] + [1]
            triangle.append(row)
        return triangle