day01.Rmd

---
title: "--- Day 1: Report Repair ---"
author: Fleur Kelpin
date: Dec 1, 2020
output: github_document
---

```{r message=FALSE, warning=FALSE}
library(tidyverse)
input <- read.csv("day01.txt")[, 1]
```

# Part 1
> Find the two entries that sum to 2020 and then multiply those two numbers together.

```{r}
input %>%
  c(., 2020 - .) %>%
  .[duplicated(.)] %>%
  prod()
```
# Part 2
> What is the product of the three entries that sum to 2020?

```{r}
input %>%
  combn(3) %>%
  .[,colSums(.) == 2020] %>%
  prod()
```