add 4th december solutions

2021-12-05 10:11:42 +01:00
parent e6563a9ad7
commit 77ed7aeeb7
3 changed files with 781 additions and 0 deletions
@@ -0,0 +1,177 @@
+package four
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func Run() {
+	draws, boards := readInput()
+
+	fmt.Printf("1st winning board: %d\n", calculateWinningBoard(findFirstWinningBoard(boards, createPlayboards(boards), draws)))
+	fmt.Printf("2nd winning board: %d\n", calculateWinningBoard(findLastWinningBoard(boards, createPlayboards(boards), draws)))
+}
+
+func calculateWinningBoard(board [][]int, playboard [][]bool, draw int) int {
+	r := 0
+	for i, row := range playboard {
+		for j, val := range row {
+			if !val {
+				r += board[i][j]
+			}
+		}
+	}
+	return r * draw
+}
+
+func isIntInSlice(i int, slice []int) bool {
+	for _, v := range slice {
+		if i == v {
+			return true
+		}
+	}
+	return false
+}
+
+func findLastWinningBoard(boards [][][]int, playboard [][][]bool, draws []int) ([][]int, [][]bool, int) {
+	winners := make([]int, 0)
+	for _, draw := range draws {
+		for i, board := range boards {
+			for j, row := range board {
+				for k, num := range row {
+					if num == draw {
+						playboard[i][j][k] = true
+						if !isIntInSlice(i, winners) && checkIfWinner(playboard[i]) {
+							winners = append(winners, i)
+							if len(winners) == len(boards) {
+								return board, playboard[i], draw
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+	return nil, nil, 0
+}
+
+func findFirstWinningBoard(boards [][][]int, playboard [][][]bool, draws []int) ([][]int, [][]bool, int) {
+	for _, draw := range draws {
+		for i, board := range boards {
+			for j, row := range board {
+				for k, num := range row {
+					if num == draw {
+						playboard[i][j][k] = true
+						if checkIfWinner(playboard[i]) {
+							return board, playboard[i], draw
+						}
+					}
+				}
+			}
+		}
+	}
+	return nil, nil, 0
+}
+
+func checkIfWinner(board [][]bool) bool {
+	// check horizontals
+	var checks int
+	for _, row := range board { // rows
+		checks = 0
+		for _, v := range row {
+			if v {
+				checks++
+			}
+		}
+		if checks == len(row) {
+			return true
+		}
+	}
+
+	for i := 0; i < len(board[0]); i++ {
+		checks = 0
+		for j := 0; j < len(board); j++ {
+			if board[j][i] == true {
+				checks++
+			}
+		}
+		if checks == len(board) {
+			return true
+		}
+	}
+	return false
+}
+func createPlayboards(boards [][][]int) [][][]bool {
+	playboard := make([][][]bool, len(boards))
+
+	for i := range playboard {
+		playboard[i] = make([][]bool, len(boards[0]))
+		for j := range playboard[i] {
+			playboard[i][j] = make([]bool, len(boards[0][0]))
+		}
+	}
+
+	return playboard
+}
+
+func readInput() ([]int, [][][]int) {
+	file, err := os.Open("./pkg/four/input.txt")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+	boards := make([][][]int, 0)
+
+	scanner := bufio.NewScanner(file)
+
+	// first line are the draws
+	scanner.Scan()
+	drawsString := scanner.Text()
+	draws := make([]int, 0)
+	for _, v := range strings.Split(drawsString, ",") {
+		n, err := strconv.Atoi(v)
+		if err != nil {
+			log.Fatal(err)
+		}
+		draws = append(draws, n)
+	}
+	scanner.Scan()
+
+	board := *new([][]int)
+
+	for scanner.Scan() {
+		if scanner.Text() == "" {
+			boards = append(boards, board)
+			board = *new([][]int)
+			continue
+		}
+		currentLine := scanner.Text()
+
+		currentLine = strings.ReplaceAll(currentLine, "  ", " ")
+		if len(currentLine) > 0 && currentLine[0] == ' ' {
+			currentLine = strings.Replace(currentLine, " ", "", 1)
+		}
+
+		splitCurrentLine := strings.Split(currentLine, " ")
+		row := *new([]int)
+		for i := 0; i < len(splitCurrentLine); i++ {
+			x, err := strconv.Atoi(splitCurrentLine[i])
+			if err != nil {
+				log.Fatal(err)
+			}
+			row = append(row, x)
+		}
+		board = append(board, row)
+	}
+
+	boards = append(boards, board)
+
+	if err := scanner.Err(); err != nil {
+		log.Fatal(err)
+	}
+	return draws, boards
+}