AdventOfCode2021/day13/day 13a/main.go
Luke Else f25f5f56b7 Day 13a updated
silly error - didn't actually affect the outcome... oh well!
2021-12-14 22:49:19 +00:00

110 lines
2.0 KiB
Go

package main
import (
"bufio"
"fmt"
"os"
"strconv"
"strings"
)
func main() {
content := returnContent("../input")
//content := returnContent("testInput")
sheet := make(map[Coordinate]bool)
answer := 0
for _, line := range *content {
if strings.HasPrefix(line, "fold") {
//Fold instructions
instruction := strings.Split(line, "=")
if strings.Contains(instruction[0], "x") {
foldPoint, _ := strconv.Atoi(instruction[1])
sheet = FoldX(sheet, foldPoint)
}
if strings.Contains(instruction[0], "y") {
foldPoint, _ := strconv.Atoi(instruction[1])
sheet = FoldY(sheet, foldPoint)
}
//Only want to consider the first instruction
//Break means that we don't end up processing the further folds
break
} else if line != "" {
//mapping instructions
coordinates := strings.Split(line, ",")
x, _ := strconv.Atoi(coordinates[0])
y, _ := strconv.Atoi(coordinates[1])
sheet[Coordinate{X: x, Y: y}] = true
}
}
for range sheet {
answer++
}
fmt.Println(answer)
}
func FoldX(sheet map[Coordinate]bool, foldPoint int) (folded map[Coordinate]bool) {
folded = make(map[Coordinate]bool)
for mark := range sheet {
x := mark.X
if x > foldPoint {
//If the value is in the region that gets folded
x = 2*foldPoint - x
}
folded[Coordinate{X: x, Y: mark.Y}] = true
}
return
}
func FoldY(sheet map[Coordinate]bool, foldPoint int) (folded map[Coordinate]bool) {
folded = make(map[Coordinate]bool)
for mark := range sheet {
y := mark.Y
if y > foldPoint {
//If the value is in the region that gets folded
y = 2*foldPoint - y
}
folded[Coordinate{X: mark.X, Y: y}] = true
}
return
}
type Coordinate struct {
X int
Y int
}
func returnContent(path string) *[]string {
//read file and return it as an array of integers
file, err := os.Open(path)
var content []string
if err != nil {
fmt.Println("Unlucky, the file didn't open")
return &content
}
defer file.Close()
scanner := bufio.NewScanner(file)
for scanner.Scan() {
content = append(content, scanner.Text())
}
return &content
}