commit cd3667464866c67838a5e60b6287fec030208510
Author: Stefan Harmuth <stefan.harmuth@docomodigital.com>
Date:   Mon Jan 4 07:50:00 2021 +0100

    day01

diff --git a/day01/day.go b/day01/day.go
new file mode 100644
index 0000000..b92d13d
--- /dev/null
+++ b/day01/day.go
@@ -0,0 +1,62 @@
+package day01
+
+import (
+	"strconv"
+	"strings"
+	"tools"
+)
+
+func getDistanceFromStart(instructions []string, breakOnRevisit bool) int {
+	x := 0
+	y := 0
+	z := 0
+	visited := tools.NewSet()
+
+	for _, instruction := range instructions {
+		switch instruction[0] {
+		case 'R':
+			z++
+			z = z % 4
+		case 'L':
+			z--
+			if z < 0 {
+				z += 4
+			}
+		}
+		distance, _ := strconv.Atoi(instruction[1:])
+		for i := 0; i < distance; i++ {
+			switch z {
+			case 0:
+				y--
+			case 1:
+				x++
+			case 2:
+				y++
+			case 3:
+				x--
+			}
+
+			if breakOnRevisit {
+				if visited.Contains(tools.Coordinate{X: x, Y: y}) {
+					return tools.Abs(x) + tools.Abs(y)
+				} else {
+					visited.Add(tools.Coordinate{X: x, Y: y})
+				}
+			}
+		}
+	}
+
+	return tools.Abs(x) + tools.Abs(y)
+}
+
+func Part1(puzzle tools.AoCPuzzle) interface{} {
+	instructions := puzzle.GetInputArray()
+
+	return getDistanceFromStart(strings.Split(instructions[0], ", "), false)
+}
+
+func Part2(puzzle tools.AoCPuzzle) interface{} {
+	instructions := puzzle.GetInputArray()
+
+	return getDistanceFromStart(strings.Split(instructions[0], ", "), true)
+}
diff --git a/inputs/1 b/inputs/1
new file mode 100644
index 0000000..34a1e76
--- /dev/null
+++ b/inputs/1
@@ -0,0 +1 @@
+R4, R4, L1, R3, L5, R2, R5, R1, L4, R3, L5, R2, L3, L4, L3, R1, R5, R1, L3, L1, R3, L1, R2, R2, L2, R5, L3, L4, R4, R4, R2, L4, L1, R5, L1, L4, R4, L1, R1, L2, R5, L2, L3, R2, R1, L194, R2, L4, R49, R1, R3, L5, L4, L1, R4, R2, R1, L5, R3, L5, L4, R4, R4, L2, L3, R78, L5, R4, R191, R4, R3, R1, L2, R1, R3, L1, R3, R4, R2, L2, R1, R4, L5, R2, L2, L4, L2, R1, R2, L3, R5, R2, L3, L3, R3, L1, L1, R5, L4, L4, L2, R5, R1, R4, L3, L5, L4, R5, L4, R5, R4, L3, L2, L5, R4, R3, L3, R1, L5, R5, R1, L3, R2, L5, R5, L3, R1, R4, L5, R4, R2, R3, L4, L5, R3, R4, L5, L5, R4, L4, L4, R1, R5, R3, L1, L4, L3, L4, R1, L5, L1, R2, R2, R4, R4, L5, R4, R1, L1, L1, L3, L5, L2, R4, L3, L5, L4, L1, R3
\ No newline at end of file
diff --git a/inputs/1_test b/inputs/1_test
new file mode 100644
index 0000000..b781c2d
--- /dev/null
+++ b/inputs/1_test
@@ -0,0 +1 @@
+R5, L5, R5, R3
\ No newline at end of file
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..54af919
--- /dev/null
+++ b/main.go
@@ -0,0 +1,82 @@
+package main
+
+import (
+	"aoc2016/day01"
+	"flag"
+	"fmt"
+	"os"
+	"path/filepath"
+	"tools"
+)
+
+var dayFunctions map[int]map[int]func(puzzle tools.AoCPuzzle) interface{}
+var day int
+var part int
+var test bool
+var timeit bool
+var timeitNumber int
+var myDir, _ = filepath.Abs(filepath.Dir(os.Args[0]))
+
+func initDayFunctions() {
+	dayFunctions = map[int]map[int]func(puzzle tools.AoCPuzzle) interface{}{
+		1: {1: day01.Part1, 2: day01.Part2},
+		//		2:  {1: day02.Part1, 2: day02.Part2},
+		//		3:  {1: day03.Part1, 2: day03.Part2},
+		//		4:  {1: day04.Part1, 2: day04.Part2},
+		//		5:  {1: day05.Part1, 2: day05.Part2},
+		//		6:  {1: day06.Part1, 2: day06.Part2},
+		//		7:  {1: day07.Part1, 2: day07.Part2},
+		//		8:  {1: day08.Part1, 2: day08.Part2},
+		//		9:  {1: day09.Part1, 2: day09.Part2},
+		//		10: {1: day10.Part1, 2: day10.Part2},
+		//		11: {1: day11.Part1, 2: day11.Part2},
+		//		12: {1: day12.Part1, 2: day12.Part2},
+		//		13: {1: day13.Part1, 2: day13.Part2},
+		//		14: {1: day14.Part1, 2: day14.Part2},
+		//		15: {1: day15.Part1, 2: day15.Part2},
+		//		16: {1: day16.Part1, 2: day16.Part2},
+		//		17: {1: day17.Part1, 2: day17.Part2},
+		//		18: {1: day18.Part1, 2: day18.Part2},
+		//		19: {1: day19.Part1, 2: day19.Part2},
+		//		20: {1: day20.Part1, 2: day20.Part2},
+		//		21: {1: day21.Part1, 2: day21.Part2},
+	}
+}
+
+func execute(thisDay int) {
+	p := tools.AoCPuzzle{}
+	if test {
+		p.FromFile = fmt.Sprintf("%s/inputs/%d_test", myDir, thisDay)
+	} else {
+		p.FromFile = fmt.Sprintf("%s/inputs/%d", myDir, thisDay)
+	}
+	p.ReadInputFromFile()
+	if part == -1 || part == 1 {
+		p.Solve(dayFunctions[thisDay][1], thisDay, 1, timeit, timeitNumber)
+	}
+	if part == -1 || part == 2 {
+		p.Solve(dayFunctions[thisDay][2], thisDay, 2, timeit, timeitNumber)
+	}
+}
+
+func main() {
+	initDayFunctions()
+	flag.IntVar(&day, "day", -1, "day to execute; -1 = all")
+	flag.IntVar(&part, "part", -1, "part to execute; -1 = all")
+	flag.BoolVar(&test, "test", false, "run the test case")
+	flag.BoolVar(&timeit, "timeit", false, "measure execution time")
+	flag.IntVar(&timeitNumber, "timeitNumber", 50, "build time average of this many runs")
+	flag.Parse()
+
+	if day != -1 {
+		if _, ok := dayFunctions[day]; !ok {
+			fmt.Printf("ERROR: unknown/invalid day: %d\n", day)
+			os.Exit(1)
+		}
+		execute(day)
+	} else {
+		for thisDay := range dayFunctions {
+			execute(thisDay)
+		}
+	}
+}