triangle

We have triangle made of blocks. The topmost row has 1 block, the next row down has 2 blocks, the next row has 3 blocks, and so on. Compute recursively (no loops or multiplication) the total number of blocks in such a triangle with the given number of rows.

triangle(0) -> 0
triangle(1) -> 1
triangle(2) -> 3

This exercise was taken from codingbat.com and has been adapted for the Python language. There are many great programming exercises there, but the majority are created for Java.

Starter Code

def triangle(rows: int) -> int:
    pass


result = triangle(0)
print(result)

Tests

from main import triangle


def test_triangle_1():
    assert triangle(0) == 0


def test_triangle_2():
    assert triangle(1) == 1


def test_triangle_3():
    assert triangle(2) == 3


def test_triangle_4():
    assert triangle(3) == 6


def test_triangle_5():
    assert triangle(4) == 10


def test_triangle_6():
    assert triangle(5) == 15


def test_triangle_7():
    assert triangle(6) == 21


def test_triangle_8():
    assert triangle(7) == 28