Day 25 (Golang)

.github/README.md

@@ -40,7 +40,7 @@ Puzzle inputs and descriptions are not included in this repository. You'll have
 | [22](/22-crabCombat)                | ![Partially complete][partial] | [Link](/22-crabCombat/python)             |                                       |                      |
 | [23](/23-crabCups)                  | ![Incomplete][cross]           |                                           |                                       |                      |
 | [24](/24-lobbyLayout)               | ![Partially complete][partial] | [Link](/24-lobbyLayout/python)            |                                       |                      |
-| 25                                  | ![Not yet attempted][pending]  |                                           |                                       |                      |
+| [25](/25-comboBreaker)              | ![Completed][check]            | [Link](/25-comboBreaker/python)           | [Link](/25-comboBreaker/go)           |                      |
 
 <!-- PARSE END -->
 

25-comboBreaker/README.md

@@ -9,7 +9,7 @@ I might go back and try some of the other challenges from this year that I didn'
 <details><summary>Script output</summary>
 
 ```
-❯ python .\python\ ft
+❯ python python ft
 AoC 2020: day 25 - Combo Breaker
 Python 3.8.5
 
@@ -17,8 +17,19 @@ Test cases
 1.1 pass in 0.0 seconds
 
 Answers
-Part 1: 297257 in 7.745995283126831 seconds
+Part 1: 297257 in 7.089499235153198 seconds
 Part 2: 0 in 0.0 seconds
+
+❯ go run .\go\ ft
+AoC 2020: day 25 - Combo Breaker
+Go go1.15.2
+
+Test cases
+1.1 pass in 0.00000000 seconds
+
+Answers
+Part 1: 297257 in 0.13749980 seconds
+Part 2: 0 in 0.00000000 seconds
 ```
 
 </details>

25-comboBreaker/go/challenge/common.go

@@ -0,0 +1,18 @@
+package challenge
+
+import (
+	"strconv"
+	"strings"
+)
+
+func parse(instr string) []int {
+	var o []int
+	for _, x := range strings.Split(strings.TrimSpace(instr), "\n") {
+		i, err := strconv.Atoi(x)
+		if err != nil {
+			panic(err)
+		}
+		o = append(o, i)
+	}
+	return o
+}

25-comboBreaker/go/challenge/partOne.go

@@ -0,0 +1,44 @@
+package challenge
+
+import "errors"
+
+func singleTransformation(v, subjectNumber int) int {
+	return (v * subjectNumber) % 20201227
+}
+
+func transform(loopSize, subjectNumber int) int {
+	v := 1
+	for i := 0; i < loopSize; i += 1 {
+		v = singleTransformation(v, subjectNumber)
+	}
+	return v
+}
+
+func findLoopSize(targetPubkey int) int {
+	var c int
+	v := 1
+	for {
+		c += 1
+		v = singleTransformation(v, 7)
+		if v == targetPubkey {
+			return c
+		}
+	}
+}
+
+func PartOne(instr string) int {
+	inputSlice := parse(instr)
+
+	pubkeyOne := inputSlice[0]
+	pubkeyTwo := inputSlice[1]
+
+	loopSizeOne := findLoopSize(pubkeyOne)
+	loopSizeTwo := findLoopSize(pubkeyTwo)
+
+	encryptionKey := transform(loopSizeTwo, pubkeyOne)
+	if encryptionKey != transform(loopSizeOne, pubkeyTwo) {
+		panic(errors.New("encryption keys do not match"))
+	}
+
+	return encryptionKey
+}

25-comboBreaker/go/challenge/partTwo.go

@@ -0,0 +1,5 @@
+package challenge
+
+func PartTwo(instr string) int {
+	return 0
+}

25-comboBreaker/go/main.go

@@ -0,0 +1,155 @@
+package main
+
+import (
+	"adventOfCode/25-comboBreaker/go/challenge"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"runtime"
+	"strconv"
+	"time"
+
+	"github.com/fatih/color"
+)
+
+var forceTime bool
+
+func main() {
+	var infoStruct info
+	{
+		inb, err := ioutil.ReadFile("info.json")
+		if err != nil {
+			fmt.Println("Error: could not open info.json")
+			os.Exit(-1)
+		}
+		err = json.Unmarshal(inb, &infoStruct)
+		if err != nil {
+			fmt.Println("Error: could not parse info.json")
+			os.Exit(-1)
+		}
+	}
+
+	var (
+		year  = infoStruct.Year
+		day   = infoStruct.Day
+		title = infoStruct.Title
+	)
+
+	fmt.Fprintf(color.Output, "%s: day %s - %s\n", color.YellowString("AoC "+year), color.BlueString(day), title)
+	fmt.Fprintf(color.Output, "Go %s\n\n", color.BlueString(runtime.Version()))
+
+	var challengeInput string
+	{
+		inb, err := ioutil.ReadFile("input.txt")
+		if err != nil {
+			fmt.Println("Error: could not open input.txt")
+			os.Exit(-1)
+		}
+		challengeInput = string(inb)
+	}
+
+	for _, v := range os.Args[1:] {
+		if v == "ft" {
+			forceTime = true
+		}
+	}
+
+	runTests(infoStruct)
+
+	fmt.Println("Answers")
+
+	fmt.Printf("Running part %s...\r", color.BlueString("1"))
+	outputString := fmt.Sprintf("Part %s: ", color.BlueString("1"))
+	x, t := runAndTime(func() int { return challenge.PartOne(challengeInput) })
+	outputString += color.BlueString(strconv.Itoa(x))
+	if t > 15 || forceTime {
+		outputString += fmt.Sprintf(" in %s seconds", color.BlueString(fmt.Sprintf("%.8f", t)))
+	}
+	for i := 0; i < 12; i += 1 {
+		outputString += " "
+	}
+	outputString += "\n"
+	fmt.Fprint(color.Output, outputString)
+
+	fmt.Printf("Running part %s...\r", color.BlueString("2"))
+	outputString = fmt.Sprintf("Part %s: ", color.BlueString("2"))
+	x, t = runAndTime(func() int { return challenge.PartTwo(challengeInput) })
+	outputString += color.BlueString(strconv.Itoa(x))
+	if t > 15 || forceTime {
+		outputString += fmt.Sprintf(" in %s seconds", color.BlueString(fmt.Sprintf("%.8f", t)))
+	}
+	for i := 0; i < 12; i += 1 {
+		outputString += " "
+	}
+	outputString += "\n"
+	fmt.Fprint(color.Output, outputString)
+
+}
+
+type tc struct {
+	Input    string `json:"input"`
+	Expected int    `json:"expected"`
+}
+
+type info struct {
+	Year      string `json:"year"`
+	Day       string `json:"day"`
+	Title     string `json:"title"`
+	TestCases struct {
+		One []tc `json:"one"`
+		Two []tc `json:"two"`
+	} `json:"testCases"`
+}
+
+func runTests(infoStruct info) {
+
+	if len(infoStruct.TestCases.One) == 0 && len(infoStruct.TestCases.Two) == 0 {
+		fmt.Println("Info: no test cases specified. Skipping tests")
+		fmt.Println()
+		return
+	}
+
+	fmt.Println("Test cases")
+
+	rt := func(tcs []tc, f func(string) int, n string) {
+		for i, tc := range tcs {
+			readable_test_num := color.BlueString(n + "." + strconv.Itoa(i+1))
+			fmt.Fprintf(color.Output, "Running %s...\r", readable_test_num)
+
+			outputString := readable_test_num + " "
+
+			result, t := runAndTime(func() int { return f(tc.Input) })
+
+			if result == tc.Expected {
+				outputString += color.GreenString("pass")
+			} else {
+				outputString += fmt.Sprintf("%s (got %s, expected %s)", color.RedString("fail"), color.BlueString(strconv.Itoa(result)), color.BlueString(strconv.Itoa(tc.Expected)))
+			}
+
+			if t > 15 || forceTime {
+				outputString += fmt.Sprintf(" in %s seconds", color.BlueString(fmt.Sprintf("%.8f", t)))
+			}
+
+			for i := 0; i < 12; i += 1 {
+				outputString += " "
+			}
+			outputString += "\n"
+
+			fmt.Fprint(color.Output, outputString)
+		}
+	}
+
+	rt(infoStruct.TestCases.One, challenge.PartOne, "1")
+	rt(infoStruct.TestCases.Two, challenge.PartTwo, "2")
+
+	fmt.Println()
+
+}
+
+func runAndTime(f func() int) (int, float64) {
+	st := time.Now()
+	x := f()
+	et := time.Now()
+	return x, et.Sub(st).Seconds()
+}