3rd: optimize embarassing binary to decimal conversion

cmd/main.go

@@ -0,0 +1,17 @@
+package main
+
+import (
+	"adventofcode/pkg/one"
+	"adventofcode/pkg/three"
+	"adventofcode/pkg/two"
+	"fmt"
+)
+
+func main() {
+	fmt.Println("Day 1")
+	one.Run()
+	fmt.Println("Day 2")
+	two.Run()
+	fmt.Println("Day 3")
+	three.Run()
+}

go.mod

@@ -0,0 +1,3 @@
+module adventofcode
+
+go 1.17

pkg/one/one.go

@@ -0,0 +1,80 @@
+package one
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+)
+
+func Run() {
+	fmt.Printf("1st solution: %d\n", solveFirst())
+	fmt.Printf("2nd solution: %d\n", solveSecond())
+}
+
+func readInput() []int {
+	file, err := os.Open("./pkg/one/input.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+	numbers := make([]int, 0)
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		num, err := strconv.Atoi(scanner.Text())
+		if err != nil {
+			log.Fatal(err)
+		}
+		numbers = append(numbers, num)
+	}
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return numbers
+}
+
+func solveFirst() int {
+	p := 0
+	i := 0
+
+	for k, v := range readInput() {
+		if k == 0 {
+			p = v
+			continue
+		}
+		if p < v {
+			i++
+		}
+		p = v
+	}
+
+	return i
+}
+
+func solveSecond() int {
+	increasedMeasurements := 0
+	a := make([]int, 3)
+	b := make([]int, 3)
+	numbers := readInput()
+
+	for i := 0; i < len(numbers); i++ {
+		if i+4 <= len(numbers) {
+			a = numbers[i : i+3]
+			b = numbers[i+1 : i+4]
+			aSum := 0
+			bSum := 0
+			for _, v := range a {
+				aSum += v
+			}
+			for _, v := range b {
+				bSum += v
+			}
+			if bSum > aSum {
+				increasedMeasurements++
+			}
+		}
+	}
+
+	return increasedMeasurements
+}

pkg/three/three.go

@@ -0,0 +1,192 @@
+package three
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func Run() {
+	values := readInput()
+	heatmap := createHeatmap(values)
+	fmt.Printf("power: %d\n", calcPower(calcGamma(heatmap, len(values)), calcEpsilon(heatmap, len(values))))
+	fmt.Printf("oxygen * co2 (life support): %d\n", calcOxygen(values)*calcCO2(values))
+}
+
+func calcOxygen(values [][]int) int {
+	valueStore := make([][][]int, 0)
+	valueStore = append(valueStore, values)
+	for i := 0; i < len(values[0]); i++ {
+		frequencyMap := getMostCommonValues(valueStore[i])
+		newValues := make([][]int, 0)
+		for _, v := range valueStore[i] {
+			if v[i] == frequencyMap[i] {
+				newValues = append(newValues, v)
+			}
+		}
+
+		valueStore = append(valueStore, newValues)
+
+		if len(newValues) == 1 {
+			break
+		}
+	}
+
+	return convertToDecimal(valueStore[len(valueStore)-1][0])
+}
+
+func calcCO2(values [][]int) int {
+	valueStore := make([][][]int, 0)
+	valueStore = append(valueStore, values)
+	for i := 0; i < len(values[0]); i++ {
+		frequencyMap := getLeastCommonValues(valueStore[i])
+		newValues := make([][]int, 0)
+		for _, v := range valueStore[i] {
+			if v[i] == frequencyMap[i] {
+				newValues = append(newValues, v)
+			}
+		}
+
+		valueStore = append(valueStore, newValues)
+
+		if len(newValues) == 1 {
+			break
+		}
+	}
+
+	return convertToDecimal(valueStore[len(valueStore)-1][0])
+}
+
+func getMostCommonValues(values [][]int) []int {
+	ones := make([]int, len(values[0]))
+	zeros := make([]int, len(values[0]))
+	result := make([]int, len(values[0]))
+	for _, v := range values {
+		for i, b := range v {
+			if b == 1 {
+				ones[i]++
+			} else if b == 0 {
+				zeros[i]++
+			}
+		}
+	}
+	for k := range result {
+		if ones[k] > zeros[k] {
+			result[k] = 1
+		} else {
+			result[k] = 0
+		}
+		if ones[k] == zeros[k] {
+			result[k] = 1
+		}
+	}
+	return result
+}
+
+func getLeastCommonValues(values [][]int) []int {
+	ones := make([]int, len(values[0]))
+	zeros := make([]int, len(values[0]))
+	result := make([]int, len(values[0]))
+	for _, v := range values {
+		for i, b := range v {
+			if b == 1 {
+				ones[i]++
+			} else if b == 0 {
+				zeros[i]++
+			}
+		}
+	}
+	for k := range result {
+		if ones[k] > zeros[k] {
+			result[k] = 0
+		} else {
+			result[k] = 1
+		}
+		if ones[k] == zeros[k] {
+			result[k] = 0
+		}
+	}
+	return result
+}
+
+func calcPower(gamma []int, epsilon []int) int {
+	return convertToDecimal(gamma) * convertToDecimal(epsilon)
+}
+
+func convertToDecimal(i []int) int {
+	s := []string{}
+	for _, v := range i {
+		s = append(s, strconv.Itoa(v))
+	}
+	r, _ := strconv.ParseInt(strings.Join(s, ""), 2, 64)
+	return int(r)
+}
+
+func calcGamma(heatmap []int, lines int) []int {
+	gamma := make([]int, len(heatmap))
+	for k, v := range heatmap {
+		if v > lines/2 {
+			gamma[k] = 1
+		} else {
+			gamma[k] = 0
+		}
+	}
+	return gamma
+}
+
+func calcEpsilon(heatmap []int, lines int) []int {
+	gamma := make([]int, len(heatmap))
+	for k, v := range heatmap {
+		if v < lines/2 {
+			gamma[k] = 1
+		} else {
+			gamma[k] = 0
+		}
+	}
+	return gamma
+}
+
+func createHeatmap(values [][]int) []int {
+	heatmap := make([]int, len(values[0]))
+	for _, v := range values {
+		for k2, v2 := range v {
+			if v2 == 1 {
+				heatmap[k2]++
+			}
+		}
+	}
+	return heatmap
+}
+
+func readInput() [][]int {
+	file, err := os.Open("./pkg/three/input.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+	values := make([][]int, 0)
+
+	scanner := bufio.NewScanner(file)
+
+	for scanner.Scan() {
+		line := strings.Split(scanner.Text(), "")
+
+		val := make([]int, 0)
+		for _, v := range line {
+			x, err := strconv.Atoi(v)
+			if err != nil {
+				log.Fatal(err)
+			}
+			val = append(val, x)
+		}
+		values = append(values, val)
+	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return values
+}

pkg/two/two.go

@@ -0,0 +1,70 @@
+package two
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func Run() {
+	commands := readInput()
+	fmt.Printf("1st final position: %d\n", solve(commands, false))
+	fmt.Printf("2nd final position: %d\n", solve(commands, true))
+}
+
+func solve(commands []string, alt bool) int {
+	depth := 0
+	horizontalPosition := 0
+	aim := 0
+
+	for _, v := range commands {
+
+		command := strings.Split(v, " ")
+
+		x, err := strconv.Atoi(command[1])
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		switch command[0] {
+		case "forward":
+			horizontalPosition += x
+			if alt {
+				depth += aim * x
+			}
+		case "up":
+			if !alt {
+				depth -= x
+			} else {
+				aim -= x
+			}
+		case "down":
+			if !alt {
+				depth += x
+			} else {
+				aim += x
+			}
+		}
+	}
+	return horizontalPosition * depth
+}
+
+func readInput() []string {
+	file, err := os.Open("./pkg/two/input.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+	commands := make([]string, 0)
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		commands = append(commands, scanner.Text())
+	}
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return commands
+}