feat: add main code

2020/day03/main.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+func parseInput(file string) []string {
+	content, err := os.ReadFile(file)
+	if err != nil {
+		log.Fatalf("Faild to read input file: %v", err)
+	}
+	lines := strings.Split(string(content), "\n")
+	var data []string
+	for _, line := range lines {
+		data = append(data, line)
+	}
+	return data
+}
+
+func PartOne(input []string) int {
+	trees := 0
+	column := 0
+	for row := range input {
+		if len(input[row]) == 0 {
+			continue
+		}
+		if input[row][column%len(input[row])] == '#' {
+			trees++
+		}
+		column += 3
+	}
+	return trees
+}
+
+func PartTwo(input []string) int {
+	result := 1
+	slopes := [][]int{{1, 1}, {3, 1}, {5, 1}, {7, 1}, {1, 2}}
+	for _, slope := range slopes {
+		trees := 0
+		column := 0
+		for row := 0; row < len(input); row += slope[1] {
+			if len(input[row]) == 0 {
+				continue
+			}
+			if input[row][column%len(input[row])] == '#' {
+				trees++
+			}
+			column += slope[0]
+		}
+		result *= trees
+	}
+	return result
+}
+
+func main() {
+	data := parseInput("input.txt")
+	fmt.Println("Part 1:", PartOne(data))
+	fmt.Println("Part 2:", PartTwo(data))
+}

2020/day03/main_test.go

@@ -0,0 +1,45 @@
+package main
+
+import "testing"
+
+func TestPartOne(t *testing.T) {
+	input := []string{
+		"..##.......",
+		"#...#...#..",
+		".#....#..#.",
+		"..#.#...#.#",
+		".#...##..#.",
+		"..#.##.....",
+		".#.#.#....#",
+		".#........#",
+		"#.##...#...",
+		"#...##....#",
+		".#..#...#.#",
+	}
+	expected := 7
+	got := PartOne(input)
+	if got != expected {
+		t.Errorf("PartOne() = %d, want %d", got, expected)
+	}
+}
+
+func TestPartTwo(t *testing.T) {
+	input := []string{
+		"..##.......",
+		"#...#...#..",
+		".#....#..#.",
+		"..#.#...#.#",
+		".#...##..#.",
+		"..#.##.....",
+		".#.#.#....#",
+		".#........#",
+		"#.##...#...",
+		"#...##....#",
+		".#..#...#.#",
+	}
+	expected := 336
+	got := PartTwo(input)
+	if got != expected {
+		t.Errorf("PartTwo() = %d, want %d", got, expected)
+	}
+}