Merge pull request #73 from tholok97/day8

Day 8 in go

Author: Arxcis

days/day-08/solutions/tholok97.go

@@ -0,0 +1,94 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"regexp"
+	"strconv"
+)
+
+type instruction struct {
+	arg int
+	op  string
+}
+
+func main() {
+	scanner := bufio.NewScanner(os.Stdin)
+
+	instructions := make([]instruction, 0)
+
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		re := regexp.MustCompile(`^(nop|acc|jmp) ([+-]\d+)$`)
+		matches := re.FindStringSubmatch(line)
+
+		arg, err := strconv.Atoi(matches[2])
+
+		if err != nil {
+			panic("Misbehaving number")
+		}
+
+		instructions = append(instructions, instruction{
+			op:  matches[1],
+			arg: arg,
+		})
+	}
+
+	_, accumulator := run(instructions)
+
+	fmt.Println(accumulator)
+
+	for i := 0; i < len(instructions); i++ {
+		swap := instructions[i].op
+
+		switch swap {
+		case "jmp":
+			instructions[i].op = "nop"
+		case "nop":
+			instructions[i].op = "jmp"
+		default:
+			continue
+		}
+
+		isInfinite, accumulator := run(instructions)
+
+		if !isInfinite {
+			fmt.Println(accumulator)
+            break
+		}
+
+		instructions[i].op = swap
+	}
+}
+
+func run(instructions []instruction) (isinfinite bool, accumulator int) {
+	curr := 0
+
+	visited := make([]bool, len(instructions))
+
+	for {
+		if curr == len(instructions) {
+			return false, accumulator
+		}
+
+		if visited[curr] {
+			return true, accumulator
+		}
+
+		visited[curr] = true
+
+		ins := instructions[curr]
+
+		switch ins.op {
+		case "acc":
+			accumulator += ins.arg
+			curr++
+		case "nop":
+			curr++
+		case "jmp":
+			curr += ins.arg
+		}
+	}
+}

days/day-08/test.sh

@@ -6,6 +6,7 @@ D=$(dirname $(realpath $0))
 
 echo ""
 echo "--- Day 8: Handheld Halting ---"
+$D/../../languages/go.sh     $D/input.txt $D/output.txt $D/solutions/tholok97.go
 $D/../../languages/sml.sh    $D/input.txt $D/output.txt $D/solutions/day08.sml
 $D/../../languages/deno.sh   $D/input.txt $D/output.txt $D/solutions/day08.ts
 echo ""