starting 2023

2023/day01/main.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	_ "embed"
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/alexchao26/advent-of-code-go/cast"
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+//go:embed input.txt
+var input string
+
+func init() {
+	// do this in init (not main) so test file has same input
+	input = strings.TrimRight(input, "\n")
+	if len(input) == 0 {
+		panic("empty input.txt file")
+	}
+}
+
+func main() {
+	var part int
+	flag.IntVar(&part, "part", 1, "part 1 or 2")
+	flag.Parse()
+	fmt.Println("Running part", part)
+
+	if part == 1 {
+		ans := part1(input)
+		util.CopyToClipboard(fmt.Sprintf("%v", ans))
+		fmt.Println("Output:", ans)
+	} else {
+		ans := part2(input)
+		util.CopyToClipboard(fmt.Sprintf("%v", ans))
+		fmt.Println("Output:", ans)
+	}
+}
+
+func part1(input string) int {
+	var sum int
+	for _, line := range strings.Split(input, "\n") {
+		var tens, ones int
+		for i := 0; i < len(line); i++ {
+			if strings.ContainsAny(line[i:i+1], "0123456789") {
+				tens = cast.ToInt(line[i : i+1])
+				break
+			}
+		}
+		for i := len(line) - 1; i >= 0; i-- {
+			if strings.ContainsAny(line[i:i+1], "0123456789") {
+				ones = cast.ToInt(line[i : i+1])
+				break
+			}
+		}
+		sum += tens*10 + ones
+	}
+
+	return sum
+}
+
+func part2(input string) int {
+	prefixes := map[string]int{
+		"one":   1,
+		"two":   2,
+		"three": 3,
+		"four":  4,
+		"five":  5,
+		"six":   6,
+		"seven": 7,
+		"eight": 8,
+		"nine":  9,
+		"zero":  0,
+	}
+	for i := 0; i <= 9; i++ {
+		prefixes[cast.ToString(i)] = i
+	}
+
+	var sum int
+	for _, line := range strings.Split(input, "\n") {
+		var first, last int
+
+		for len(line) > 0 {
+			for prefix, val := range prefixes {
+				if doesStringHavePrefix(line, prefix) {
+					if first == 0 {
+						first = val
+					}
+					last = val
+					break
+				}
+			}
+
+			// shorten line
+			line = line[1:]
+		}
+
+		sum += first*10 + last
+	}
+
+	return sum
+}
+
+func doesStringHavePrefix(str string, prefix string) bool {
+	if len(str) < len(prefix) {
+		return false
+	}
+	return str[:len(prefix)] == prefix
+}

2023/day01/main_test.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"testing"
+)
+
+var example = `1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet`
+
+func Test_part1(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{
+			name:  "example",
+			input: example,
+			want:  142,
+		},
+		{
+			name:  "actual",
+			input: input,
+			want:  55488,
+		},
+	}
+	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)
+			}
+		})
+	}
+}
+
+var example2 = `two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen`
+
+func Test_part2(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  int
+	}{
+		{
+			name:  "example",
+			input: example2,
+			want:  281,
+		},
+		{
+			name:  "actual",
+			input: input,
+			want:  55614,
+		},
+	}
+	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)
+			}
+		})
+	}
+}