Day 1. Report Repair

Problem statement

https://adventofcode.com/2020/day/1 (mirror)

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My solution

A very simple introductory probem. There is nothing special or hard to understand.

The most efficient solution for Part A should probaby involve creating a hashset of complementary numbers (a complementary number for x would be (2020 - x)); for Part B consult this wikipedia article to find an efficient algorithm for finding three numbers in a list that sum to a given number.

That said, the input list is short enough that a simple nested for loop gets the result quickly.