day 2 part 1

day02.go

@@ -0,0 +1,68 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+)
+
+func validgame(totalred, totalgreen, totalblue int, r io.Reader) bool {
+	scanner := bufio.NewScanner(r)
+	scanner.Split(bufio.ScanWords)
+
+	for {
+		if !scanner.Scan() {
+			break
+		}
+
+		num, _ := strconv.Atoi(scanner.Text())
+
+		scanner.Scan()
+		switch scanner.Text() {
+		case "red":
+			if num > totalred {
+				return false
+			}
+		case "green":
+			if num > totalgreen {
+				return false
+			}
+		case "blue":
+			if num > totalblue {
+				return false
+			}
+		}
+
+	}
+	return true
+}
+
+type day02 struct{}
+
+func (d day02) solve1(r io.Reader) string {
+	var (
+		totalred   = 12
+		totalgreen = 13
+		totalblue  = 14
+		gameSum    = 0
+		scanner    = bufio.NewScanner(r)
+		replacer   = strings.NewReplacer(",", " ", ";", " ")
+	)
+
+	for gameN := 1; scanner.Scan(); gameN++ {
+		line := scanner.Text()
+		_, game, _ := strings.Cut(line, ": ")
+		sr := strings.NewReader(replacer.Replace(game))
+		if validgame(totalred, totalgreen, totalblue, sr) {
+			gameSum += gameN
+		}
+	}
+
+	return fmt.Sprintf("%d", gameSum)
+}
+
+func (d day02) solve2(r io.Reader) string {
+	return ""
+}

main_test.go

@@ -35,3 +35,21 @@ func TestDay01(t *testing.T) {
 		t.Errorf("day 1 solution 2 = %s; wanted %s", res2, ans2)
 	}
 }
+
+func TestDay02(t *testing.T) {
+	ans1 := "8"
+	input1 := `Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
+Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
+Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
+Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
+Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green`
+
+	puzzle := day02{}
+
+	res1 := puzzle.solve1(strings.NewReader(input1))
+	t.Logf("day 2 solution 1: %s", res1)
+	if res1 != ans1 {
+		t.Errorf("day 2 solution 1 = %s; wanted %s", res1, ans1)
+	}
+
+}