day 4 p1

Author: smyachenkov

day4/Day4p1.go

@@ -0,0 +1,150 @@
+package main
+
+import (
+	"bufio"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const boardSize = 5
+
+type GameState struct {
+	boards       [][][]int
+	boardNumbers map[int]map[int][]int // number to board id to [row col]
+	boardResult  [][]int               // matrix id to [] with boardSize * 2 len.
+}
+
+/*        * [01] -> inc (0 + row) inc (3 + col)
+		[101] 2
+		[010] 2
+		[111] 3
+         222
+
+		[223222]
+		boardResult = {0, {223222}}
+*/
+
+func main() {
+	file, _ := os.Open("input.txt")
+	scanner := bufio.NewScanner(file)
+
+	// numbers
+	scanner.Scan()
+	numbers := parseNumbersLine(scanner.Text())
+
+	// boards
+	boards := parseBoards(*scanner)
+
+	// init numbers map
+	numbersMap := map[int]map[int][]int{}
+	for i, board := range boards {
+		for row := 0; row < boardSize; row++ {
+			for col := 0; col < boardSize; col++ {
+				n := board[row][col]
+				if _, ok := numbersMap[n]; !ok {
+					numbersMap[n] = map[int][]int{}
+				}
+				numbersMap[n][i] = []int{row, col}
+			}
+		}
+	}
+
+	boardResult := make([][]int, len(boards))
+	for i := 0; i < len(boards); i++ {
+		boardResult[i] = make([]int, 2*boardSize)
+	}
+
+	gameState := GameState{
+		boards:       boards,
+		boardNumbers: numbersMap,
+		boardResult:  boardResult,
+	}
+
+	// process input
+	calledNumbers := []int{}
+	winner := -1
+	for _, n := range numbers {
+		calledNumbers = append(calledNumbers, n)
+		affectedBoards := gameState.boardNumbers[n]
+		for boardId, rowcol := range affectedBoards {
+			row := rowcol[0]
+			col := rowcol[1]
+			boardRes := gameState.boardResult[boardId]
+			boardRes[row]++
+			boardRes[boardSize+col]++
+			if boardRes[row] == boardSize || boardRes[boardSize+col] == boardSize {
+				winner = boardId
+				break
+			}
+		}
+		if winner != -1 {
+			break
+		}
+	}
+	println("Winner board id: " + strconv.Itoa(winner))
+
+	score := calculateScore(gameState.boards[winner], calledNumbers)
+	println(score)
+}
+
+func parseNumbersLine(s string) []int {
+	numbersStrings := strings.Split(s, ",")
+	result := make([]int, len(numbersStrings))
+	for i := range numbersStrings {
+		n, _ := strconv.Atoi(numbersStrings[i])
+		result[i] = n
+	}
+	return result
+}
+
+func parseBoards(s bufio.Scanner) [][][]int {
+	result := [][][]int{}
+	for s.Scan() {
+		board := [][]int{}
+		for i := 0; i < boardSize; i++ {
+			s.Scan()
+			line := parseBoardLine(s.Text())
+			board = append(board, line)
+		}
+		result = append(result, board)
+
+	}
+	return result
+}
+
+func parseBoardLine(s string) []int {
+	numbersStrings := strings.Fields(s)
+	result := make([]int, len(numbersStrings))
+	for i := range numbersStrings {
+		n, _ := strconv.Atoi(numbersStrings[i])
+		result[i] = n
+	}
+	return result
+}
+
+func calculateScore(board [][]int, calledNumbers []int) int {
+	winningNumber := calledNumbers[len(calledNumbers)-1]
+	unmarkedNumbers := map[int]bool{}
+
+	// at start all numbers are unmarked
+	for row := 0; row < boardSize; row++ {
+		for col := 0; col < boardSize; col++ {
+			n := board[row][col]
+			unmarkedNumbers[n] = true
+		}
+	}
+
+	// exclude all called numbers
+	for _, v := range calledNumbers {
+		unmarkedNumbers[v] = false
+	}
+
+	unmkarkedSum := 0
+	for k, v := range unmarkedNumbers {
+		if v {
+			unmkarkedSum += k
+		}
+	}
+	return unmkarkedSum * winningNumber
+}