2015-day02: simple geometry calcs

2015/day02/main.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/alexchao26/advent-of-code-go/mathutil"
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+func main() {
+	var part int
+	flag.IntVar(&part, "part", 1, "part 1 or 2")
+	flag.Parse()
+	fmt.Println("Running part", part)
+
+	var ans int
+	if part == 1 {
+		ans = part1(util.ReadFile("./input.txt"))
+	} else {
+		ans = part2(util.ReadFile("./input.txt"))
+	}
+	fmt.Println("Output:", ans)
+}
+
+func part1(input string) int {
+	var totalSqFt int
+	for _, line := range strings.Split(input, "\n") {
+		var x, y, z int
+		_, err := fmt.Sscanf(line, "%dx%dx%d", &x, &y, &z)
+		if err != nil {
+			panic(err)
+		}
+		totalSqFt += x * y * 2
+		totalSqFt += x * z * 2
+		totalSqFt += z * y * 2
+		totalSqFt += mathutil.MinInt(x*y, y*z, x*z) // slack in wrapping paper...
+	}
+
+	return totalSqFt
+}
+
+func part2(input string) int {
+	var totalLen int
+	for _, line := range strings.Split(input, "\n") {
+		var x, y, z int
+		_, err := fmt.Sscanf(line, "%dx%dx%d", &x, &y, &z)
+		if err != nil {
+			panic(err)
+		}
+		cubic := x * y * z
+		totalLen += cubic
+		sides := []int{
+			2 * (x + y),
+			2 * (y + z),
+			2 * (x + z),
+		}
+		totalLen += mathutil.MinInt(sides...)
+	}
+	return totalLen
+}

2015/day02/main_test.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+var example = `2x3x4
+1x1x10`
+
+func Test_part1(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{"example", example, 58 + 43},
+		{"actual", util.ReadFile("input.txt"), 1588178},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := part1(tt.input); got != tt.want {
+				t.Errorf("part1() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_part2(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{"actual", util.ReadFile("input.txt"), 3783758},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := part2(tt.input); got != tt.want {
+				t.Errorf("part2() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}