driscollis/adventofcode2020

Hi, I'm Mike!

I am the author of the popular Python blog, The Mouse vs the Python. You can follow me on Twitter or check out my YouTube Channel where you can learn Python.

adventofcode2020's Issues

Use generator for day 1

Loved your day 1 blog post and code!

I noticed a quick way to improve the performance, by turning a list into a generator since only one answer is needed to be computed (in case there is more than one answer) and the search for more than the first answer can be deferred. Here's my benchmark and result:

import timeit
import math
from itertools import combinations


def get_answer(numbers: list[int], combos: int = 2) -> int:
    result = [pair for pair in combinations(numbers, combos) if sum(pair) == 2020]

    multiplied = math.prod(result[0])

    return multiplied


def generator_get_answer(numbers: list[int], combos: int = 2) -> int:
    result = (pair for pair in combinations(numbers, combos) if sum(pair) == 2020)

    multiplied = math.prod(next(result))

    return multiplied


if __name__ == "__main__":
    with open("input.txt") as f:
        numbers = [int(item.strip()) for item in f.readlines()]

    n = 100
    print(f"list: {timeit.timeit(lambda: get_answer(numbers, combos=3), number=n)}")
    print(
        f"generator: {timeit.timeit(lambda: generator_get_answer(numbers, combos=3), number=n)}"
    )

Result:

list: 25.837099567
generator: 21.768024056000005