aoc-2022/day10/solution.go

package day10

import (
	"fmt"
	"strconv"
	"strings"
)

type Solver struct {
	ops []Op
}

type Op struct {
	opcode  string
	operand int
}

func (s *Solver) ParseInput(input []string) {
	s.ops = make([]Op, len(input))

	for i, line := range input {
		splits := strings.Split(line, " ")
		opcode := splits[0]
		switch opcode {
		case "noop":
			s.ops[i] = Op{opcode, 0}
		case "addx":
			operand, _ := strconv.Atoi(splits[1])
			s.ops[i] = Op{opcode, operand}
		}
	}
}

const maxCycles = 220

func (s *Solver) SolvePart1() any {
	cycleValuesForX := s.getXValues()

	return getSignalStrength(cycleValuesForX)
}

func (s *Solver) getXValues() []int {
	var cycleValuesForX = make([]int, 0)
	X := 1

	cycleNum := 0

	for _, op := range s.ops {
		switch op.opcode {
		case "noop":
			cycleValuesForX = append(cycleValuesForX, X)
			cycleNum += 1
		case "addx":
			cycleValuesForX = append(cycleValuesForX, X, X)
			cycleNum += 2

			X += op.operand
		}
	}

	for cycleNum <= 2*maxCycles {
		cycleValuesForX = append(cycleValuesForX, X)
		cycleNum++
	}
	return cycleValuesForX
}

func getSignalStrength(xValues []int) int {
	const start = 20
	const step = 40

	var total int
	for i := start; i <= maxCycles; i += step {
		total += i * xValues[i-1]
	}
	return total
}

func (s *Solver) SolvePart2() any {
	cycleValuesForX := s.getXValues()

	for r := 0; r < 6; r++ {
		for c := 0; c < 40; c++ {
			cycle := 40*r + c
			xValue := cycleValuesForX[cycle]
			if c >= xValue-1 && c <= xValue+1 {
				fmt.Print("#")
			} else {
				fmt.Print(" ")
			}
		}
		fmt.Println()
	}
	return "RGLRBZAU"
}