refactor: massive refactor to have only one binary to call

internal/2021/DayOne/code.go

@@ -0,0 +1,43 @@
+package dayone
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	registry.Register("2021D1", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []int {
+	content, _ := os.ReadFile(filepath)
+	var data []int
+	for line := range strings.SplitSeq(string(content), "\n") {
+		num, _ := strconv.Atoi(line)
+		data = append(data, num)
+	}
+	return data
+}
+
+func PartOne(data []int) int {
+	count := 0
+	for i := 1; i < len(data); i++ {
+		if data[i] > data[i-1] {
+			count++
+		}
+	}
+	return count
+}
+
+func PartTwo(data []int) int {
+	count := 0
+	for i := 3; i < len(data); i++ {
+		if data[i] > data[i-3] {
+			count++
+		}
+	}
+	return count
+}
+

internal/2021/DayOne/code_test.go

@@ -0,0 +1,22 @@
+package dayone
+
+import "testing"
+
+var testInput = []int{199, 200, 208, 210, 200, 207, 240, 269, 260, 263}
+
+func TestPartOne(t *testing.T) {
+	expected := 7
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}
+
+func TestPartTwo(t *testing.T) {
+	expected := 5
+	got := PartTwo(testInput)
+	if got != expected {
+		t.Errorf("PartTwo() = %d, want %d", got, expected)
+	}
+}
+

internal/2021/DayThree/code.go

@@ -0,0 +1,117 @@
+package daythree
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"strings"
+)
+
+func init() {
+	registry.Register("2021D3", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []string {
+	content, _ := os.ReadFile(filepath)
+	return strings.Split(strings.TrimSpace(string(content)), "\n")
+}
+
+func PartOne(data []string) int {
+	bitlen := len(data[0])
+	ones := make([]int, bitlen)
+
+	for _, line := range data {
+		for i := range bitlen {
+			if line[i] == '1' {
+				ones[i]++
+			}
+		}
+	}
+
+	var gamma int
+	total := len(data)
+	for idx := range bitlen {
+		gamma <<= 1
+		if ones[idx] > total-ones[idx] {
+			gamma |= 1
+		}
+	}
+
+	mask := (1 << bitlen) - 1
+	epsilon := mask ^ gamma
+	return gamma * epsilon
+}
+
+func PartTwo(data []string) int {
+	bitlen := len(data[0])
+
+	oxygenIndices := make([]int, len(data))
+	for idx := range oxygenIndices {
+		oxygenIndices[idx] = idx
+	}
+
+	co2Indices := make([]int, len(data))
+	for idx := range co2Indices {
+		co2Indices[idx] = idx
+	}
+
+	for indice := 0; indice < bitlen && len(oxygenIndices) > 1; indice++ {
+		ones := 0
+		for _, idx := range oxygenIndices {
+			if data[idx][indice] == '1' {
+				ones++
+			}
+		}
+		target := byte('1')
+		if ones*2 < len(oxygenIndices) {
+			target = '0'
+		}
+		writeIdx := 0
+		for readIdx := 0; readIdx < len(oxygenIndices); readIdx++ {
+			if data[oxygenIndices[readIdx]][indice] == target {
+				oxygenIndices[writeIdx] = oxygenIndices[readIdx]
+				writeIdx++
+			}
+		}
+		oxygenIndices = oxygenIndices[:writeIdx]
+	}
+
+	for idx := 0; idx < bitlen && len(co2Indices) > 1; idx++ {
+		ones := 0
+		for _, indice := range co2Indices {
+			if data[indice][idx] == '1' {
+				ones++
+			}
+		}
+		target := byte('0')
+		if ones*2 < len(co2Indices) {
+			target = '1'
+		}
+		writeIdx := 0
+		for readIdx := 0; readIdx < len(co2Indices); readIdx++ {
+			if data[co2Indices[readIdx]][idx] == target {
+				co2Indices[writeIdx] = co2Indices[readIdx]
+				writeIdx++
+			}
+		}
+		co2Indices = co2Indices[:writeIdx]
+	}
+
+	oxygenRating := 0
+	for _, char := range data[oxygenIndices[0]] {
+		oxygenRating <<= 1
+		if char == '1' {
+			oxygenRating |= 1
+		}
+	}
+
+	co2Rating := 0
+	for _, char := range data[co2Indices[0]] {
+		co2Rating <<= 1
+		if char == '1' {
+			co2Rating |= 1
+		}
+	}
+
+	return oxygenRating * co2Rating
+}
+

internal/2021/DayThree/code_test.go

@@ -0,0 +1,35 @@
+package daythree
+
+import "testing"
+
+var testInput = []string{
+	"00100",
+	"11110",
+	"10110",
+	"10111",
+	"10101",
+	"01111",
+	"00111",
+	"11100",
+	"10000",
+	"11001",
+	"00010",
+	"01010",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 198
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}
+
+func TestPartTwo(t *testing.T) {
+	expected := 230
+	got := PartTwo(testInput)
+	if got != expected {
+		t.Errorf("PartTwo() = %d, want %d", got, expected)
+	}
+}
+

internal/2021/DayTwo/code.go

@@ -0,0 +1,60 @@
+package daytwo
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	registry.Register("2021D2", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []string {
+	content, _ := os.ReadFile(filepath)
+	return strings.Split(string(content), "\n")
+}
+
+func PartOne(data []string) int {
+	horizontal := 0
+	depth := 0
+	for _, line := range data {
+		parts := strings.Split(line, " ")
+		direction := parts[0]
+		amount, _ := strconv.Atoi(parts[1])
+		switch direction {
+		case "forward":
+			horizontal += amount
+		case "down":
+			depth += amount
+		case "up":
+			depth -= amount
+		}
+	}
+	return horizontal * depth
+}
+
+func PartTwo(data []string) int {
+	horizontal := 0
+	depth := 0
+	aim := 0
+
+	for _, line := range data {
+		parts := strings.Split(line, " ")
+		direction := parts[0]
+		amount, _ := strconv.Atoi(parts[1])
+
+		switch direction {
+		case "forward":
+			horizontal += amount
+			depth += aim * amount
+		case "down":
+			aim += amount
+		case "up":
+			aim -= amount
+		}
+	}
+	return horizontal * depth
+}
+

internal/2021/DayTwo/code_test.go

@@ -0,0 +1,29 @@
+package daytwo
+
+import "testing"
+
+var testInput = []string{
+	"forward 5",
+	"down 5",
+	"forward 8",
+	"up 3",
+	"down 8",
+	"forward 2",
+}
+
+func TestPartOne(t *testing.T) {
+	expected := 150
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}
+
+func TestPartTwo(t *testing.T) {
+	expected := 900
+	got := PartTwo(testInput)
+	if got != expected {
+		t.Errorf("PartTwo() = %d, want %d", got, expected)
+	}
+}
+