2 files changed, 165 insertions, 0 deletions
diff --git a/go/2023/internal/day_06/part_02/part_02.go b/go/2023/internal/day_06/part_02/part_02.go
new file mode 100644
index 0000000..316b169
--- /dev/null
+++ b/go/2023/internal/day_06/part_02/part_02.go
@@ -0,0 +1,81 @@
+package part_02
+
+import (
+	"os"
+	"strconv"
+	"strings"
+)
+
+const USE_SAMPLE = false
+
+/**
+ * Tried:
+ * - 24655068 (correct!)
+ */
+func Solve() {
+	var filePath string
+	if USE_SAMPLE {
+		filePath = "../_input/day_06_part_02_sample.txt"
+	} else {
+		filePath = "../_input/day_06.txt"
+	}
+	contents, _ := os.ReadFile(filePath)
+
+	lines := strings.Split(string(contents), "\r\n")
+
+	timeLine := lines[0]
+	time := parseTimeLine(timeLine)
+
+	distLine := lines[1]
+	distance := parseDistanceLine(distLine)
+
+	answer := calculateAnswer(time, distance)
+
+	println(answer)
+}
+
+func parseTimeLine(timeLine string) int {
+	prefix := "Time:"
+	return parseLine(prefix, timeLine)
+}
+
+func parseDistanceLine(distLine string) int {
+	prefix := "Distance:"
+	return parseLine(prefix, distLine)
+}
+
+func parseLine(prefix string, line string) int {
+	withoutTitle := strings.TrimPrefix(line, prefix)
+
+	numbers := []string{}
+	for _, number := range strings.Split(withoutTitle, " ") {
+		if number == "" {
+			continue
+		}
+		numbers = append(numbers, number)
+	}
+
+	number := strings.Join(numbers, "")
+	numberInt, err := strconv.Atoi(number)
+	if err != nil {
+		panic(err)
+	}
+
+	return numberInt
+}
+
+func calculateAnswer(maxTime int, recordDistance int) int {
+	var greaterThanRecord []int
+	for buttonPressedFor := 0; buttonPressedFor <= maxTime; buttonPressedFor++ {
+		distance := calculateDistance(buttonPressedFor, maxTime)
+		if distance > recordDistance {
+			greaterThanRecord = append(greaterThanRecord, distance)
+		}
+	}
+
+	return len(greaterThanRecord)
+}
+
+func calculateDistance(buttonPressedFor int, maxTime int) int {
+	return buttonPressedFor * (maxTime - buttonPressedFor)
+}
diff --git a/go/2023/internal/day_06/part_02/part_02_test.go b/go/2023/internal/day_06/part_02/part_02_test.go
new file mode 100644
index 0000000..67924dc
--- /dev/null
+++ b/go/2023/internal/day_06/part_02/part_02_test.go
@@ -0,0 +1,84 @@
+package part_02
+
+import "testing"
+
+func TestParseTimeLine(t *testing.T) {
+	tests := map[string]struct {
+		input    string
+		expected int
+	}{
+		"sample": {"Time:      7  15   30", 71530},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			actual := parseTimeLine(test.input)
+			if actual != test.expected {
+				t.Errorf("Expected %d, got %d", test.expected, actual)
+			}
+		})
+	}
+}
+
+func TestParseDistLine(t *testing.T) {
+	tests := map[string]struct {
+		input    string
+		expected int
+	}{
+		"sample": {"Distance:  9  40  200", 940200},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			actual := parseDistanceLine(test.input)
+			if actual != test.expected {
+				t.Errorf("Expected %d, got %d", test.expected, actual)
+			}
+		})
+	}
+}
+
+func TestCalculateAnswer(t *testing.T) {
+	tests := map[string]struct {
+		maxTime        int
+		recordDistance int
+		expected       int
+	}{
+		"sample": {71530, 940200, 71503},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			actual := calculateAnswer(test.maxTime, test.recordDistance)
+			if actual != test.expected {
+				t.Errorf("Expected %d, got %d", test.expected, actual)
+			}
+		})
+	}
+}
+
+func TestCalculateDistance(t *testing.T) {
+	tests := map[string]struct {
+		maxTime          int
+		buttonPressedFor int
+		expected         int
+	}{
+		"7_7": {7, 7, 0},
+		"7_6": {7, 6, 6},
+		"7_5": {7, 5, 10},
+		"7_4": {7, 4, 12},
+		"7_3": {7, 3, 12},
+		"7_2": {7, 2, 10},
+		"7_1": {7, 1, 6},
+		"7_0": {7, 0, 0},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			actual := calculateDistance(test.buttonPressedFor, test.maxTime)
+			if actual != test.expected {
+				t.Errorf("Expected %d, got %d", test.expected, actual)
+			}
+		})
+	}
+}