day six done

06/main.go

@@ -0,0 +1,100 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+)
+
+func main() {
+	partOne()
+	partTwo()
+}
+
+func unique(s string) string {
+	result := ""
+
+	for _, r := range s {
+		if !strings.ContainsRune(result, r) {
+			result = result + string(r)
+		}
+	}
+
+	return result
+}
+
+func union(s, q string) string {
+	result := ""
+
+	for _, r := range s {
+		if strings.ContainsRune(q, r) {
+			result = result + string(r)
+		}
+	}
+
+	return result
+}
+
+// For each of the people in their group, you write down the questions for which they answer "yes", one per line. For example:
+// abcx
+// abcy
+// abcz
+// In this group, there are 6 questions to which anyone answered "yes": a, b, c, x, y, and z.
+// (Duplicate answers to the same question don't count extra; each question counts at most once.)
+// Another group asks for your help, then another, and eventually you've collected answers from every group on the plane (your puzzle input).
+// Each group's answers are separated by a blank line, and within each group, each person's answers are on a single line.
+
+func partOne() {
+	f, _ := os.Open("input")
+	reader := bufio.NewReader(f)
+	scanner := bufio.NewScanner(reader)
+
+	sum := 0
+	currentForm := ""
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			sum = sum + len(unique(currentForm))
+			currentForm = ""
+		} else {
+			currentForm = currentForm + line
+		}
+	}
+	sum = sum + len(unique(currentForm))
+
+	fmt.Println(sum)
+}
+
+// As you finish the last group's customs declaration, you notice that you misread one word in the instructions:
+// You don't need to identify the questions to which anyone answered "yes";
+// you need to identify the questions to which everyone answered "yes"!
+
+func partTwo() {
+	f, _ := os.Open("input")
+	reader := bufio.NewReader(f)
+	scanner := bufio.NewScanner(reader)
+
+	sum := 0
+	var currentForm string
+	newgroup := true
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if newgroup {
+			currentForm = line
+			newgroup = false
+		} else {
+			if line != "" {
+				currentForm = union(currentForm, line)
+			} else {
+				sum = sum + len(currentForm)
+				newgroup = true
+			}
+		}
+	}
+	sum = sum + len(currentForm)
+
+	fmt.Println(sum)
+}