AdventOfCode2022/11/main.go

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Go
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2022-12-17 23:13:43 +00:00
package main
import (
"bufio"
"fmt"
"os"
"strconv"
"strings"
"time"
)
func mustAtoi(line string) int {
i, _ := strconv.Atoi(line)
return i
}
func main() {
start := time.Now()
partOne()
duration := time.Since(start)
partTwo()
duration2 := time.Since(start)
fmt.Printf("p1: %s, p2: %s\n", duration, duration2-duration)
}
func makeScanner(test bool) *bufio.Scanner {
var f *os.File
if test {
f, _ = os.Open("inputs/testinput")
} else {
f, _ = os.Open("inputs/input")
}
reader := bufio.NewReader(f)
return bufio.NewScanner(reader)
}
type monkey struct {
items []int
operation string // either "plus", "times", or "square"
value int // ignored for "square"
test int // "divisible by <test>"
testpass int // monkey to throw to if test passes
testfail int // monkey to throw to if test fails
inspections int
}
func partOne() {
scanner := makeScanner(false)
currentMonkey := 0
monkeys := []monkey{}
// parse monkeys
for scanner.Scan() {
line := scanner.Text()
switch {
case strings.HasPrefix(line, "M"):
currentMonkey = mustAtoi(strings.Trim(line, "Monkey :"))
monkeys = append(monkeys, monkey{items: make([]int, 0)})
case strings.HasPrefix(line, " S"):
_, after, _ := strings.Cut(line, ":")
items := strings.Split(after, ",")
for _, i := range items {
monkeys[currentMonkey].items = append(monkeys[currentMonkey].items, mustAtoi(strings.TrimSpace(i)))
}
case strings.HasPrefix(line, " O"):
if strings.Contains(line, "+") {
monkeys[currentMonkey].operation = "plus"
l := strings.Split(line, " ")
monkeys[currentMonkey].value = mustAtoi(l[len(l)-1])
} else if strings.Contains(line, "old * old") {
monkeys[currentMonkey].operation = "square"
} else if strings.Contains(line, "*") {
monkeys[currentMonkey].operation = "times"
l := strings.Split(line, " ")
monkeys[currentMonkey].value = mustAtoi(l[len(l)-1])
}
case strings.HasPrefix(line, " T"):
l := strings.Split(line, " ")
monkeys[currentMonkey].test = mustAtoi(l[len(l)-1])
case strings.HasPrefix(line, " If t"):
l := strings.Split(line, " ")
monkeys[currentMonkey].testpass = mustAtoi(l[len(l)-1])
case strings.HasPrefix(line, " If f"):
l := strings.Split(line, " ")
monkeys[currentMonkey].testfail = mustAtoi(l[len(l)-1])
}
}
for i := 0; i < 20; i++ {
for m := range monkeys {
monkeys[m].inspections += len(monkeys[m].items)
for _, i := range monkeys[m].items {
if monkeys[m].operation == "plus" {
i = (i + monkeys[m].value) / 3
}
if monkeys[m].operation == "times" {
i = (i * monkeys[m].value) / 3
}
if monkeys[m].operation == "square" {
i = (i * i) / 3
}
if i%monkeys[m].test == 0 {
monkeys[monkeys[m].testpass].items = append(monkeys[monkeys[m].testpass].items, i)
} else {
monkeys[monkeys[m].testfail].items = append(monkeys[monkeys[m].testfail].items, i)
}
}
monkeys[m].items = []int{}
}
}
one, two := 0, 0
for _, m := range monkeys {
if m.inspections > one && m.inspections > two {
one, two = two, m.inspections
} else if m.inspections > one {
one = m.inspections
}
}
fmt.Println(one * two)
}
func partTwo() {
scanner := makeScanner(false)
currentMonkey := 0
monkeys := []monkey{}
// parse monkeys
for scanner.Scan() {
line := scanner.Text()
switch {
case strings.HasPrefix(line, "M"):
currentMonkey = mustAtoi(strings.Trim(line, "Monkey :"))
monkeys = append(monkeys, monkey{items: make([]int, 0)})
case strings.HasPrefix(line, " S"):
_, after, _ := strings.Cut(line, ":")
items := strings.Split(after, ",")
for _, i := range items {
monkeys[currentMonkey].items = append(
monkeys[currentMonkey].items, mustAtoi(strings.TrimSpace(i)),
)
}
case strings.HasPrefix(line, " O"):
if strings.Contains(line, "+") {
monkeys[currentMonkey].operation = "plus"
l := strings.Split(line, " ")
monkeys[currentMonkey].value = mustAtoi(l[len(l)-1])
} else if strings.Contains(line, "old * old") {
monkeys[currentMonkey].operation = "square"
} else if strings.Contains(line, "*") {
monkeys[currentMonkey].operation = "times"
l := strings.Split(line, " ")
monkeys[currentMonkey].value = mustAtoi(l[len(l)-1])
}
case strings.HasPrefix(line, " T"):
l := strings.Split(line, " ")
monkeys[currentMonkey].test = mustAtoi(l[len(l)-1])
case strings.HasPrefix(line, " If t"):
l := strings.Split(line, " ")
monkeys[currentMonkey].testpass = mustAtoi(l[len(l)-1])
case strings.HasPrefix(line, " If f"):
l := strings.Split(line, " ")
monkeys[currentMonkey].testfail = mustAtoi(l[len(l)-1])
}
}
common := 1
for i := range monkeys {
common = common * monkeys[i].test
}
for j := 0; j < 10000; j++ {
for m := range monkeys {
monkeys[m].inspections += len(monkeys[m].items)
for _, i := range monkeys[m].items {
if monkeys[m].operation == "plus" {
i = i + monkeys[m].value
}
if monkeys[m].operation == "times" {
i = i * monkeys[m].value
}
if monkeys[m].operation == "square" {
i = i * i
}
if i%monkeys[m].test == 0 {
monkeys[monkeys[m].testpass].items = append(monkeys[monkeys[m].testpass].items, i%common)
} else {
monkeys[monkeys[m].testfail].items = append(monkeys[monkeys[m].testfail].items, i%common)
}
}
monkeys[m].items = []int{}
}
}
one, two := 0, 0
for _, m := range monkeys {
if m.inspections > one && m.inspections > two {
one, two = two, m.inspections
} else if m.inspections > one {
one = m.inspections
}
}
fmt.Println(one * two)
}