test: Add unit test for PartTwo

2020/day05/main.go

@@ -50,7 +50,36 @@ func PartOne(input []string) int {
 	return maxSeatID
 }
 
+func PartTwo(input []string) int {
+	seatIDs := make(map[int]bool)
+	minSeatID := 1000
+	maxSeatID := 0
+
+	for _, pass := range input {
+		if len(pass) < 10 {
+			continue
+		}
+		seatID := calculateSeatID(pass)
+		seatIDs[seatID] = true
+		if seatID < minSeatID {
+			minSeatID = seatID
+		}
+		if seatID > maxSeatID {
+			maxSeatID = seatID
+		}
+	}
+
+	for seatID := minSeatID + 1; seatID < maxSeatID; seatID++ {
+		if !seatIDs[seatID] && seatIDs[seatID-1] && seatIDs[seatID+1] {
+			return seatID
+		}
+	}
+
+	return 0
+}
+
 func main() {
 	input := parseInput("input.txt")
 	fmt.Println("Part 1:", PartOne(input))
+	fmt.Println("Part 2:", PartTwo(input))
 }

2020/day05/main_test.go

@@ -2,17 +2,33 @@ package main
 
 import "testing"
 
-var testInput = []string{
+func TestPartOne(t *testing.T) {
+	input := []string{
 		"FBFBBFFRLR",
 		"BFFFBBFRRR",
 		"FFFBBBFRRR",
 		"BBFFBBFRLL",
 	}
-
-func TestPartOne(t *testing.T) {
 	expected := 820
-	got := PartOne(testInput)
+	got := PartOne(input)
 	if got != expected {
 		t.Errorf("PartOne() = %d, want %d", got, expected)
 	}
 }
+
+func TestPartTwo(t *testing.T) {
+	input := []string{
+		"FFFFFFFLLL",
+		"FFFFFFFLLR",
+		"FFFFFFFLRL",
+		"FFFFFFFLRR",
+		"FFFFFFFRLR",
+		"FFFFFFFRRL",
+		"FFFFFFFRRR",
+	}
+	expected := 4
+	got := PartTwo(input)
+	if got != expected {
+		t.Errorf("PartTwo() = %d, want %d", got, expected)
+	}
+}