6 files changed, 108 insertions, 0 deletions
diff --git a/day03/Dockerfile b/day03/Dockerfile
new file mode 100644
index 0000000..e5adcb1
--- /dev/null
+++ b/day03/Dockerfile
@@ -0,0 +1,7 @@
+FROM ruby:2.6.5-slim
+
+WORKDIR /opt
+
+COPY . .
+
+ENTRYPOINT ["./entrypoint"]
diff --git a/day03/Makefile b/day03/Makefile
new file mode 100644
index 0000000..d8adac3
--- /dev/null
+++ b/day03/Makefile
@@ -0,0 +1,14 @@
+DAY = 03
+
+.PHONY: run clean
+
+run: build
+	docker run -it --rm aoc2019day$(DAY)
+
+build: part* input
+	docker build -t aoc2019day$(DAY) .
+	touch build
+
+clean:
+	docker image rm -f aoc2019day$(DAY)
+	rm -f build
diff --git a/day03/entrypoint b/day03/entrypoint
new file mode 100755
index 0000000..8982d21
--- /dev/null
+++ b/day03/entrypoint
@@ -0,0 +1,13 @@
+#!/bin/bash
+
+if [ -x part1 ] ; then
+	echo -ne "Part 1:\n\t"
+	time ./part1 < input
+fi
+if [ -x part1 -a -x part2 ] ; then
+	echo
+fi
+if [ -x part2 ] ; then
+	echo -ne "Part 2:\n\t"
+	time ./part2 < input
+fi
diff --git a/day03/input b/day03/input
new file mode 100644
index 0000000..e023935
--- /dev/null
+++ b/day03/input
@@ -0,0 +1,2 @@
+R990,U408,L583,U275,R483,U684,R437,U828,R108,U709,R378,U97,R252,D248,R413,U750,R428,D545,R570,D795,L204,D975,L557,U160,L861,U106,R436,U934,R81,D237,R660,U704,L451,U135,R282,D391,R39,D109,R125,U918,R214,U481,R853,U825,L91,D763,R335,U868,R42,U218,R152,D429,R414,D607,R28,U436,R7,U770,L215,D373,R209,U440,L536,U120,R900,D46,R635,D75,R58,U267,L581,U474,L858,U172,R725,U54,R291,D274,L583,D743,L130,U563,R137,U524,R659,D997,R131,D364,R883,D222,R628,U579,R801,D890,L519,D749,L620,U60,L759,D759,R376,U769,L910,D570,L814,U954,L153,D42,L784,D66,L844,U29,L794,D342,L924,U825,R447,U828,R404,D52,L330,D876,R125,U203,R245,U936,R866,D804,L186,U693,L620,D722,L32,D735,L191,D217,R68,U209,L736,U365,R280,U608,L450,D240,L282,U434,R589,U94,R470,D5,R49,U407,R552,D651,L69,U518,L358,D130,L710,D929,L315,U345,L511,D229,L557,U44,L890,D702,L181,D61,L208,U553,R878,U354,R787,U624,L961,D92,L891,U70,R203,U255,R532,U154,R299,U934,L609,D985,R115,U757,L13,D368,R936,D742,L412,U346,R56,D67,R371,D175,R868,U107,R806,D530,L40,U153,R374,D223,R517,D481,L194,U545,L356,U906,L999,D885,R967,U407,L141,U927,L489,U959,L992,U638,R332,U51,R256,U901,L891,U803,L885,U804,L242,U180,R277,U693,R935,D253,L68,D153,L614,D596,L999,D633,R995,D803,R17,U303,L569,U231,R737,D970,L45,D860,L225,D65,R41,D313,R698,D340,R599,D531,R55,D568,L911,D547,R196,D228,R868,D227,R262,U525,R104,D625,R570,U968,L276,D586,R690,D73,L336,U287,R294,U148,R781,D395,R478,D804,L429,U872,L351,D910,L597,U726,L320,D964,R928,U2,R540,D325,L222
+L998,U662,R342,U104,R140,U92,R67,D102,L225,U265,R641,U592,L295,D77,R415,U908,L640,D381,R312,U44,R424,D847,R892,D625,L337,D344,L917,D914,R127,D273,L627,U812,L200,D262,R226,U273,R911,U597,L888,U28,R921,U464,R254,U771,R818,D808,L239,D225,L280,U785,R322,D831,L622,U506,R139,U12,L491,D572,L172,U685,R54,U747,L812,D717,R874,U428,L867,U174,R360,D36,R217,D539,R210,D791,L82,D665,L190,D313,R649,U849,R63,U385,R105,U806,L207,U697,L823,D272,R830,D952,L386,U987,R775,U517,R139,D756,R545,D973,L743,D286,R261,U448,R946,U884,L903,D142,R28,D374,R259,U403,R689,D245,L302,D134,R710,U762,L67,D561,R801,D140,L887,U346,L227,U682,L350,D218,L711,U755,R226,D277,R114,D61,R992,U602,L191,U640,R733,D329,R862,U242,R754,D161,L52,D974,L251,D444,L552,U977,R174,U483,R869,D955,R925,U693,R610,D353,L843,U148,L866,D167,R412,D31,L847,D979,L282,D797,L837,U473,L402,U193,L332,D603,R48,D589,L760,D673,L843,U428,R779,D592,L688,D141,R851,D642,R559,U939,R999,D64,L297,U817,R670,U322,L768,D936,L39,U95,L342,U849,L692,U714,L732,D734,L373,U66,L577,D453,R336,U760,L217,U542,R920,U24,R529,D594,L34,D79,R877,D965,R932,U460,R879,U26,R803,U876,L780,U956,L235,D270,L315,D577,R835,U750,R414,D584,L828,U335,L563,U238,L815,U780,L550,U18,R743,D54,L816,U344,L806,D197,L518,D682,L835,U255,L666,U442,L286,D543,R102,D52,L570,D787,L763,D223,R279,D892,L828,D111,L554,D452,R575,D299,R932,D187,L439,U616,L278,D701,L360,D524,L891,U953,L896,U788,R776,U782,L71,D741,L652,U121,R669,D809,L662,U319,R392,D313,R870,U794,R937,D469,R571,D761,R947
diff --git a/day03/part1 b/day03/part1
new file mode 100755
index 0000000..94d3b37
--- /dev/null
+++ b/day03/part1
@@ -0,0 +1,35 @@
+#!/usr/bin/env ruby
+
+input = $stdin.readlines.map(&:strip).map{|x|x.split(",")}
+
+def map_wire(wire_segments)
+  wire = []
+  x = 0
+  y = 0
+  wire_segments.each do |seg|
+    dir = seg[0]
+    len = seg[1..-1].to_i
+    len.times do
+      case dir
+      when "R"
+        x += 1
+      when "L"
+        x -= 1
+      when "U"
+        y += 1
+      when "D"
+        y -= 1
+      end
+      wire << [x, y]
+    end
+  end
+  wire
+end
+
+wire1 = map_wire(input[0])
+wire2 = map_wire(input[1])
+
+intersections = wire1 & wire2
+dists = intersections.map{|x,y| x.abs + y.abs} - [0]
+
+puts dists.min
diff --git a/day03/part2 b/day03/part2
new file mode 100755
index 0000000..a772a1e
--- /dev/null
+++ b/day03/part2
@@ -0,0 +1,37 @@
+#!/usr/bin/env ruby
+
+input = $stdin.readlines.map(&:strip).map{|x|x.split(",")}
+
+def map_wire(wire_segments)
+  wire = []
+  x = 0
+  y = 0
+  wire_segments.each do |seg|
+    dir = seg[0]
+    len = seg[1..-1].to_i
+    len.times do
+      case dir
+      when "R"
+        x += 1
+      when "L"
+        x -= 1
+      when "U"
+        y += 1
+      when "D"
+        y -= 1
+      end
+      wire << [x, y]
+    end
+  end
+  wire
+end
+
+wire1 = map_wire(input[0])
+wire2 = map_wire(input[1])
+
+intersections = (wire1 & wire2) - [0,0]
+steps = intersections.map do |i|
+  wire1.index(i) + wire2.index(i) + 2
+end
+
+puts steps.min