2021 Day 6 Complete!

2021/day06/input

@@ -0,0 +1 @@
+5,3,2,2,1,1,4,1,5,5,1,3,1,5,1,2,1,4,1,2,1,2,1,4,2,4,1,5,1,3,5,4,3,3,1,4,1,3,4,4,1,5,4,3,3,2,5,1,1,3,1,4,3,2,2,3,1,3,1,3,1,5,3,5,1,3,1,4,2,1,4,1,5,5,5,2,4,2,1,4,1,3,5,5,1,4,1,1,4,2,2,1,3,1,1,1,1,3,4,1,4,1,1,1,4,4,4,1,3,1,3,4,1,4,1,2,2,2,5,4,1,3,1,2,1,4,1,4,5,2,4,5,4,1,2,1,4,2,2,2,1,3,5,2,5,1,1,4,5,4,3,2,4,1,5,2,2,5,1,4,1,5,1,3,5,1,2,1,1,1,5,4,4,5,1,1,1,4,1,3,3,5,5,1,5,2,1,1,3,1,1,3,2,3,4,4,1,5,5,3,2,1,1,1,4,3,1,3,3,1,1,2,2,1,2,2,2,1,1,5,1,2,2,5,2,4,1,1,2,4,1,2,3,4,1,2,1,2,4,2,1,1,5,3,1,4,4,4,1,5,2,3,4,4,1,5,1,2,2,4,1,1,2,1,1,1,1,5,1,3,3,1,1,1,1,4,1,2,2,5,1,2,1,3,4,1,3,4,3,3,1,1,5,5,5,2,4,3,1,4

2021/day06/main.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	h "git.bullercodeworks.com/brian/adventofcode/helpers"
+)
+
+func main() {
+	inp := h.StdinToStringSlice()[0]
+	fishStr := strings.Split(inp, ",")
+	part1(fishStr)
+	part2(fishStr)
+}
+
+func part1(fishStr []string) {
+	var fish []int
+	for i := range fishStr {
+		fish = append(fish, h.Atoi(fishStr[i]))
+	}
+	for i := 0; i < 80; i++ {
+		var newFish int
+		for l := range fish {
+			if fish[l] == 0 {
+				fish[l] = 6
+				newFish++
+			} else {
+				fish[l]--
+			}
+		}
+		for ; newFish > 0; newFish-- {
+			fish = append(fish, 8)
+		}
+	}
+	fmt.Println()
+	fmt.Println("# Part 1")
+	fmt.Println(len(fish), "fish")
+	fmt.Println()
+}
+
+// For 256 days there are too many to do it the same way. Instead we track the number of fish per cycle
+func part2(fishStr []string) {
+	var fish []int
+	for i := range fishStr {
+		fish = append(fish, h.Atoi(fishStr[i]))
+	}
+	fishMap := make(map[int]int)
+	for i := 0; i < 9; i++ {
+		fishMap[i] = 0
+	}
+	for i := range fish {
+		fishMap[fish[i]]++
+	}
+
+	for i := 0; i < 256; i++ {
+		zeros := fishMap[0]
+		fishMap[0] = fishMap[1]
+		fishMap[1] = fishMap[2]
+		fishMap[2] = fishMap[3]
+		fishMap[3] = fishMap[4]
+		fishMap[4] = fishMap[5]
+		fishMap[5] = fishMap[6]
+		fishMap[6] = fishMap[7] + zeros
+		fishMap[7] = fishMap[8]
+		fishMap[8] = zeros
+	}
+	fmt.Println()
+	fmt.Println("# Part2")
+	total := 0
+	for k := range fishMap {
+		total += fishMap[k]
+	}
+	fmt.Println(total, "fish")
+}
+
+func printStatus(fish map[int]int) {
+	var total int
+	for i := 0; i < 8; i++ {
+		fmt.Printf("[%d: %d] ", i, fish[i])
+		total += fish[i]
+	}
+	fmt.Println("Total:", total)
+}

2021/day06/testinput

@@ -0,0 +1 @@
+3,4,3,1,2