pgoultiaev/aoc2017

package main

import (
    "bufio"
    "log"
    "os"
    "strconv"
    "strings"
)

func main() {
    file, err := os.Open("23.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer file.Close()

    scanner := bufio.NewScanner(file)

    instructions := [][]string{}
    for scanner.Scan() {
        slicedString := strings.Split(scanner.Text(), " ")
        instructions = append(instructions, slicedString)
    }

    mulInvoked := solve(instructions)
    println(mulInvoked)

    println(solve2())
}

func solve2() int {
    h := 0
    b := (79 * 100) + 100000
    c := b + 17000 // sub b -17 1000 times

    g := b - c
    for g != 0 {
        f0 := false

        for d := 2; (d * d) < b; d++ {
            if (b % d) == 0 {
                f0 = true
                break
            }
        }
        if f0 {
            h++
        }
        g = b - c
        b += 17
    }

    return h
}

// Part one
func solve(instructions [][]string) (mulInvoked int) {
    registers := map[string]int{}
    i := 0
    for i < len(instructions) {
        instr := instructions[i]
        x := instr[1]

        switch instr[0] {
        case "set":
            registers[x] = getInstructionValue(instr[2], registers)
        case "sub":
            registers[x] -= getInstructionValue(instr[2], registers)
        case "mul":
            registers[x] *= getInstructionValue(instr[2], registers)
            mulInvoked++
        case "jnz":
            if getInstructionValue(x, registers) != 0 {
                i += getInstructionValue(instr[2], registers) - 1
            }
        }
        i++
    }

    return mulInvoked
}

func getInstructionValue(y string, registers map[string]int) int {
    setVal, err := strconv.Atoi(y)
    if err != nil {
        return registers[y]
    }
    return setVal
}