AdventOfCode2021/day04/4b/main.go
2021-12-16 19:55:49 +00:00

163 lines
3.1 KiB
Go

package main
import (
"bufio"
"fmt"
"os"
"regexp"
"strconv"
"strings"
)
func main() {
content := returnContent("../input")
//content := returnContent("../testInput")
boards, nums := loadBoards(content)
fmt.Println(run(boards, nums))
}
func run(boards *[]Board, nums []int) int {
var completedBoards map[*Board]bool = make(map[*Board]bool)
var bingo []int
var n int
for i := 0; i < len(nums); i++ {
bingo = callNumber(nums[i], boards)
for X := 0; X < len(bingo); X++ {
_, present := completedBoards[&(*boards)[bingo[X]]]
if !present {
n = nums[i]
fmt.Println("found value", bingo, n, returnAnswer(&(*boards)[bingo[X]], n))
}
completedBoards[&(*boards)[bingo[X]]] = true
}
}
//return the answer
return returnAnswer(&(*boards)[bingo[0]], n)
}
func loadBoards(content *[]string) (boards *[]Board, nums []int) {
boards = new([]Board)
newBoard := Board{
Hash: make(map[int]location, 25),
}
boardNum := 0
row := 0
for i := 0; i < len(*content); i++ {
if i == 0 {
//add nums
numlist := strings.Split((*content)[i], ",")
for i := 0; i < len(numlist); i++ {
num, _ := strconv.Atoi(numlist[i])
nums = append(nums, num)
}
i++
} else {
if (*content)[i] != "" {
regex := regexp.MustCompile("([0-9]+)")
values := regex.FindAllString((*content)[i], 5)
for j := 0; j < len(values); j++ {
value, _ := strconv.Atoi(values[j])
newBoard.Values[row][j] = boardValue{Value: value, Visited: false}
newBoard.Hash[value] = location{x: row, y: j}
}
row++
if row == 5 {
boardNum++
i++
*boards = append(*boards, newBoard)
newBoard = Board{
Hash: make(map[int]location, 25),
}
row = 0
}
}
}
}
return
}
func callNumber(n int, boards *[]Board) (cards []int) {
for i := 0; i < len(*boards); i++ {
location, present := (*boards)[i].Hash[n]
if present {
//Change the value to visited
(*boards)[i].Values[location.x][location.y].Visited = true
if checkBingo(&(*boards)[i], location.x, location.y) {
cards = append(cards, i)
}
}
}
return
}
func checkBingo(board *Board, x int, y int) bool {
checkVertical := true
//check if bingo for a given row and column
//Check row
for i := 0; i < 5; i++ {
if !(*board).Values[x][i].Visited {
checkVertical = false
break
}
}
checkHorizontal := true
//Check column
for i := 0; i < 5; i++ {
if !(*board).Values[i][y].Visited {
checkHorizontal = false
break
}
}
return (checkVertical || checkHorizontal)
}
func returnAnswer(board *Board, n int) (answer int) {
for i := 0; i < 5; i++ {
for j := 0; j < 5; j++ {
if !(*board).Values[i][j].Visited {
answer += (*board).Values[i][j].Value
}
}
}
answer = answer * n
return
}
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
}