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solutions/day10/day10.go

@@ -0,0 +1,98 @@
+package day10
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func clearLine(line *[]rune) {
+	for idx := range *line {
+		(*line)[idx] = '.'
+	}
+}
+
+func printLine(line *[]rune) {
+	for _, c := range *line {
+		fmt.Printf("%c", c)
+	}
+	fmt.Println()
+}
+
+func registerCycle(cycle int, x int, line *[]rune) int {
+	result := 0
+	var position int
+
+	for position = cycle - 1; position > 40; position -= 40 {
+	}
+
+	if cycle == 20 || (cycle > 20 && ((cycle-20)%40 == 0)) {
+		result = x * cycle
+		//fmt.Println("register cycle", cycle, "value of x is", x, "signal strength is", result)
+	}
+
+	//if position == 0 {
+	//	fmt.Println("position is", position, "and x is", x)
+	//}
+
+	if position >= x-1 && position <= x+1 {
+		(*line)[position] = '#'
+	}
+
+	if position == 40 {
+		printLine(line)
+		clearLine(line)
+	}
+
+	return result
+}
+
+func Run(filename string) {
+	file, err := os.Open(filename)
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+		return
+	}
+
+	scanner := bufio.NewScanner(file)
+	scanner.Split(bufio.ScanLines)
+	cycle := 1
+	x := 1
+	signalStrengthSum := 0
+	currentLine := []rune{'.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.', '.'}
+	if len(currentLine) != 40 {
+		fmt.Println("line length", len(currentLine))
+		return
+	}
+
+	registerCycle(cycle, x, &currentLine)
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		if strings.HasPrefix(line, "addx ") {
+			cycle += 1
+			signalStrengthSum += registerCycle(cycle, x, &currentLine)
+			cycle += 1
+			mod, err := strconv.Atoi(string(line[5:]))
+			if err != nil {
+				fmt.Println("Invalid x modifier", err, "having read", string(line[5:]))
+				return
+			}
+			x += mod
+			signalStrengthSum += registerCycle(cycle, x, &currentLine)
+		} else if strings.HasPrefix(line, "noop") {
+			cycle += 1
+			signalStrengthSum += registerCycle(cycle, x, &currentLine)
+		} else {
+			fmt.Println("PANIC: Unknown instruction:", line)
+			return
+		}
+	}
+
+	file.Close()
+	//printLine(line)
+
+	fmt.Println("Signal strength fun", signalStrengthSum)
+}