feat: add main code

2020/day01/main.go

@@ -0,0 +1,58 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func parseInput(file string) []int {
+	content, err := os.ReadFile(file)
+	if err != nil {
+		log.Fatalf("Failed to read input file: %v", err)
+	}
+	lines := strings.Fields(string(content))
+	var data []int
+	for _, line := range lines {
+		num, err := strconv.Atoi(line)
+		if err != nil {
+			log.Fatalf("Failed to convert string to int: %v", err)
+		}
+		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
+}
+
+func main() {
+	data := parseInput("input.txt")
+	fmt.Println("Part 1:", PartOne(data))
+	fmt.Println("Part 2:", PartTwo(data))
+}