From b52a39cceed8cc2b4f0ea89fd07d7d00e38f5e8b Mon Sep 17 00:00:00 2001
From: Karl Spickermann <karlhspickermann@gmail.de>
Date: Sun, 13 Dec 2020 15:52:15 +0100
Subject: [PATCH] Day13

---
 day13/day13.go       | 81 ++++++++++++++++++++++++++++++++++++++++++++
 day13/day13Input.txt |  2 ++
 day13/day13Test.txt  |  2 ++
 3 files changed, 85 insertions(+)
 create mode 100644 day13/day13.go
 create mode 100644 day13/day13Input.txt
 create mode 100644 day13/day13Test.txt

diff --git a/day13/day13.go b/day13/day13.go
new file mode 100644
index 0000000..73cfdc2
--- /dev/null
+++ b/day13/day13.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"AoC2020/helper"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	args := os.Args[1:]
+	input, err := helper.GetInput(args[0])
+	if err != nil {
+		fmt.Println(err)
+	}
+	part1(input)
+	part2(input)
+}
+
+func checkCorrect(time int, bustimes []int) bool {
+	p := 0
+	fmt.Print(bustimes)
+	for _, bustime := range bustimes {
+		if time%bustime > p {
+			return false
+		}
+		p = time % bustime
+	}
+	return true
+}
+
+func part2(input []string) {
+	busses := strings.Split(input[1], ",")
+	var busTimes []int
+	for _, val := range busses {
+		if val != "x" {
+			busTime, _ := strconv.Atoi(val)
+			busTimes = append(busTimes, busTime)
+		} else {
+			busTimes = append(busTimes, 0)
+		}
+	}
+	step := busTimes[0]
+	time := 0
+	for i, val := range busTimes[1:] {
+		if val != 0 {
+			fmt.Printf("Value: %d Step: %d \n",val,step)
+			for (time+i+1)%val != 0 {
+				time += step
+			}
+			step = step * val
+		}
+	}
+	fmt.Println(time)
+}
+
+func part1(input []string) {
+	arrival, _ := strconv.Atoi(input[0])
+	busses := strings.Split(input[1], ",")
+	minWaitTime := 999
+	choosenBus := 0
+	for _, val := range busses {
+		if val != "x" {
+			busTime, _ := strconv.Atoi(val)
+			diff := arrival / busTime
+			waitTime := busTime*(diff+1) - arrival
+			if minWaitTime > waitTime {
+				minWaitTime = waitTime
+				choosenBus = busTime
+			}
+		}
+	}
+	fmt.Println(minWaitTime*choosenBus)
+}
+
+func timestampToMinutes(timeStamp string) int {
+	hours := int(timeStamp[0] - '0')
+	minutes, _ := strconv.Atoi(string(timeStamp[1:]))
+	return hours*60 + minutes
+}
diff --git a/day13/day13Input.txt b/day13/day13Input.txt
new file mode 100644
index 0000000..7e74881
--- /dev/null
+++ b/day13/day13Input.txt
@@ -0,0 +1,2 @@
+1000390
+23,x,x,x,x,x,x,x,x,x,x,x,x,41,x,x,x,x,x,x,x,x,x,383,x,x,x,x,x,x,x,x,x,x,x,x,13,17,x,x,x,x,19,x,x,x,x,x,x,x,x,x,29,x,503,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,37
diff --git a/day13/day13Test.txt b/day13/day13Test.txt
new file mode 100644
index 0000000..e473080
--- /dev/null
+++ b/day13/day13Test.txt
@@ -0,0 +1,2 @@
+939
+7,13,x,x,59,x,31,19
\ No newline at end of file