[2020-12-06] Add solutions for day06

Makefile

@@ -18,6 +18,8 @@ day05:
 	go run main.go day05 input
 
 day06:
+	go run main.go day06 input
+
 day07:
 day08:
 day09:

day06/example.txt

@@ -0,0 +1,15 @@
+abc
+
+a
+b
+c
+
+ab
+ac
+
+a
+a
+a
+a
+
+b

day06/parse.go

@@ -0,0 +1,48 @@
+package day06
+
+import (
+	"git.elis.nu/etu/aoc2020/utils"
+)
+
+// Build voting groups where we store tho gorup size, the question
+// that got votes, and how many votes each question got.
+type Group struct {
+	Size  int
+	Votes map[byte]int
+}
+
+var rows []Group
+
+func ParseFile(input string) {
+	row := Group{
+		Size:  0,
+		Votes: make(map[byte]int),
+	}
+
+	// Parse file
+	for _, line := range utils.GetLinesFromFile("day06/" + input + ".txt") {
+		// Commit group to list on group change
+		if line == "" {
+			rows = append(rows, row)
+
+			row = Group{
+				Size:  0,
+				Votes: make(map[byte]int),
+			}
+
+			continue
+		}
+
+		// Increment group size
+		row.Size++
+
+		// Go through votes
+		for i := 0; i < len(line); i++ {
+			// Increment vote count
+			row.Votes[line[i]]++
+		}
+	}
+
+	// Don't drop last entry
+	rows = append(rows, row)
+}

day06/solve1.go

@@ -0,0 +1,16 @@
+package day06
+
+import (
+	"log"
+)
+
+func Solve1() {
+	counter := 0
+
+	for _, row := range rows {
+		// Sum the amount of votes in total
+		counter += len(row.Votes)
+	}
+
+	log.Printf("2020-12-06.01: Answer: %d\n", counter)
+}

day06/solve2.go

@@ -0,0 +1,22 @@
+package day06
+
+import (
+	"log"
+)
+
+func Solve2() {
+	counter := 0
+
+	for _, row := range rows {
+		// Get the amount of votes on each question
+		for _, amount := range row.Votes {
+			// Check that everyone voted yes on that
+			if amount == row.Size {
+				// If so, increment counter
+				counter++
+			}
+		}
+	}
+
+	log.Printf("2020-12-06.02: Answer: %d\n", counter)
+}

main.go

@@ -9,6 +9,7 @@ import (
 	"git.elis.nu/etu/aoc2020/day03"
 	"git.elis.nu/etu/aoc2020/day04"
 	"git.elis.nu/etu/aoc2020/day05"
+	"git.elis.nu/etu/aoc2020/day06"
 	"git.elis.nu/etu/aoc2020/utils"
 )
 
@@ -32,5 +33,8 @@ func main() {
 
 	case "day05":
 		utils.Perf("2020-12-05", day05.ParseFile, day05.Solve1, day05.Solve2)
+
+	case "day06":
+		utils.Perf("2020-12-06", day06.ParseFile, day06.Solve1, day06.Solve2)
 	}
 }