refactor: massive refactor to have only one binary to call

internal/2020/DayOne/code.go

@@ -0,0 +1,50 @@
+package dayone
+
+import (
+	"advent-of-code/internal/registry"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func init() {
+	registry.Register("2020D1", ParseInput, PartOne, PartTwo)
+}
+
+func ParseInput(filepath string) []int {
+	content, _ := os.ReadFile(filepath)
+	lines := strings.Fields(string(content))
+	var data []int
+	for _, line := range lines {
+		num, _ := strconv.Atoi(line)
+		data = append(data, num)
+	}
+	return data
+}
+
+func PartOne(data []int) int {
+	seen := make(map[int]bool)
+	for _, number := range data {
+		complement := 2020 - number
+		if seen[complement] {
+			return number * complement
+		}
+		seen[number] = true
+	}
+	return 0
+}
+
+func PartTwo(data []int) int {
+	seen := make(map[int]bool)
+	for idx := range data {
+		for _, number := range data[idx+1:] {
+			complement := 2020 - data[idx] - number
+			if seen[complement] {
+				return complement * data[idx] * number
+			}
+		}
+		seen[data[idx]] = true
+	}
+	return 0
+}
+

internal/2020/DayOne/code_test.go

@@ -0,0 +1,22 @@
+package dayone
+
+import "testing"
+
+var testInput = []int{1721, 979, 366, 299, 675, 1456}
+
+func TestPartOne(t *testing.T) {
+	expected := 514579
+	got := PartOne(testInput)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}
+
+func TestPartTwo(t *testing.T) {
+	expected := 241861950
+	got := PartTwo(testInput)
+	if got != expected {
+		t.Errorf("PartTwo() = %d, want %d", got, expected)
+	}
+}
+