pascals-triangle.py

import unittest
from typing import List


class Solution:
    def generate(self, numRows: int) -> List[List[int]]:
        result = [[1] * (row + 1) for row in range(numRows)]

        for row in range(1, numRows):
            for pos in range(1, row):
                result[row][pos] = result[row - 1][pos - 1]
                result[row][pos] += result[row - 1][pos]

        return result


class TestSolution(unittest.TestCase):
    def setUp(self):
        self.sol = Solution()

    def test_zero(self):
        assert self.sol.generate(0) == []

    def test_one(self):
        assert self.sol.generate(1) == [[1]]

    def test_two(self):
        assert self.sol.generate(2) == [[1], [1, 1]]

    def test_three(self):
        assert self.sol.generate(3) == [
            [1],
            [1, 1],
            [1, 2, 1],
        ]

    def test_four(self):
        assert self.sol.generate(4) == [
            [1],
            [1, 1],
            [1, 2, 1],
            [1, 3, 3, 1],
        ]

    def test_five(self):
        assert self.sol.generate(5) == [
            [1],
            [1, 1],
            [1, 2, 1],
            [1, 3, 3, 1],
            [1, 4, 6, 4, 1],
        ]

    def test_six(self):
        assert self.sol.generate(6) == [
            [1],
            [1, 1],
            [1, 2, 1],
            [1, 3, 3, 1],
            [1, 4, 6, 4, 1],
            [1, 5, 10, 10, 5, 1],
        ]


if __name__ == "__main__":
    unittest.main()