# Advent of Code 2019-03 with R & JavaScript

**Colin Fay**, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here)

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Solving Advent of Code 2019-03 with R and JavaScript.

[Disclaimer] Obviously, this post contains a big spoiler about Advent

of Code, as it gives solutions for solving day 3.

[Disclaimer bis] I’m no JavaScript expert so this might not be the

perfect solution. TBH, that’s also the case for the R solution.

## About the JavaScript code

The JavaScript code has been written in the same RMarkdown as the R

code. It runs thanks to the `{bubble}`

package:

https://github.com/ColinFay/bubble

## Instructions

Find the instructions at: https://adventofcode.com/2019/day/3

## R solution

### Part one

library(magrittr) ipt <- scan( "input3.txt", what = character(), sep = "\n") first <- strsplit(ipt[1], split = ",")[[1]] sec <- strsplit(ipt[2], split = ",")[[1]] directions <- function(ipt, x, y){ dir <- substr(ipt, 1, 1) how_m <- as.numeric(substr(ipt, 2, nchar(ipt))) if (dir == "R"){ x <- x + how_m } else if (dir == "L"){ x <- x - how_m } else if (dir == "U"){ y <- y + how_m } else if (dir == "D"){ y <- y - how_m } return(list(x = x, y = y)) } get_dir <- function(vec){ out <- data.frame( x = 0, y = 0 ) for (i in seq_along(vec)){ y_m_1 <- out$y[nrow(out)] x_m_1 <- out$x[nrow(out)] res <- directions(vec[i], x = x_m_1, y = y_m_1) out %<>% rbind( data.frame( x = x_m_1:res$x, y = y_m_1:res$y )[-1, ] ) } out$step <- 1:nrow(out) out } out_a <- get_dir(first) out_b <- get_dir(sec) res <- merge(out_a, out_b, by = c("x", "y")) res$path <- abs(res$x) + abs(res$y) sort(unique(res$path))[2] ## [1] 386

### Part two

res$tot_step <- res$step.x + res$step.y sort(unique(res$tot_step))[2] ## [1] 6486

## JS solution

Sorry today I didn’t have time to work on the JS solution… Finding the R

solution was already quite a challenge 🙂

Here is the beginning of a code to solve the problem. Might get back to

it

later!

### Part one & Two

var res = fs.readFileSync("input3.txt", 'utf8').split("\n").filter(x => x.length != 0); var first = res[0].split(",").filter(x => x.length != 0); var sec = res[1].split(",").filter(x => x.length != 0); function directions(ipt, x, y){ var dir = ipt.substring(0,1) var how_m = parseInt(ipt.substring(1, ipt.length)) if (dir == "R"){ var x = x + how_m } else if (dir == "L"){ var x = x - how_m } else if (dir == "U"){ var y = y + how_m } else if (dir == "D"){ var y = y - how_m } var ret = {x : x, y : y}; return ret } function get_out(vec){ var out = { x: [0], y: [0] } for (var i= 0; i < vec.length; i++){ var y_m_1 = out["y"][ out[["y"]].length - 1 ] var x_m_1 = out["x"][ out[["x"]].length - 1 ] var res = directions(vec[i], x = x_m_1, y = y_m_1) out.x.push(res.x); out.y.push(res.y); } return out } var dir_f = get_out(first); var dir_s = get_out(sec);

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**Colin Fay**.

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