advent_of_code_2024/day_14/solution.go

package day_14

import (
	"fmt"
	"strings"
)

type Robot struct {
	pX, pY int
	vX, vY int
}

// task:https://adventofcode.com/2024/day/14
func SolveBasic(input string) int {
	return solveBasic(input, 101, 103)
}

// task:https://adventofcode.com/2024/day/14
func SolveBasicSmall(input string) int {
	return solveBasic(input, 11, 7)
}

func solveBasic(input string, width int, height int) int {
	robots := loadRobots(input)
	quads := []int{0, 0, 0, 0, 0}
	for _, r := range robots {
		r.pX = (r.pX + 100*r.vX) % width
		r.pY = (r.pY + 100*r.vY) % height
		if r.pX < 0 {
			r.pX += width
		}
		if r.pY < 0 {
			r.pY += height
		}
		quad := determineQuad(r, width, height)
		quads[quad]++
	}
	return quads[0] * quads[1] * quads[2] * quads[3]
}

func determineQuad(r Robot, width int, height int) int {
	if r.pX < width/2 && r.pY < height/2 {
		return 0
	}
	if r.pX > width/2 && r.pY < height/2 {
		return 1
	}
	if r.pX < width/2 && r.pY > height/2 {
		return 2
	}
	if r.pX > width/2 && r.pY > height/2 {
		return 3
	}
	return 4
}

func loadRobots(input string) []Robot {
	var robots []Robot
	for _, line := range strings.Split(input, "\n") {
		r := Robot{}
		_, err := fmt.Sscanf(line, "p=%d,%d v=%d,%d", &r.pX, &r.pY, &r.vX, &r.vY)
		if err != nil {
			panic(err)
		}
		robots = append(robots, r)
	}
	return robots
}

// task:https://adventofcode.com/2024/day/12#part2
func SolveComplex(input string) int {
	robots := loadRobots(input)
	for i := 0; i < 100000; i++ {
		if hasLine(robots) {
			printRobots(i, robots)
		}
		step(robots)
	}
	return 0
}

func hasLine(robots []Robot) bool {
	rows := map[int]int{}
	cols := map[int]int{}
	for _, r := range robots {
		rows[r.pX]++
		cols[r.pY]++
	}
	has10Row := 0
	has10Col := 0
	for _, v := range rows {
		if v >= 15 {
			has10Row++
		}
	}
	for _, v := range cols {
		if v >= 15 {
			has10Col++
		}
	}
	return has10Col >= 2 && has10Row >= 2
}

func step(robots []Robot) {
	for i, r := range robots {
		r.pX = (r.pX + r.vX) % 101
		r.pY = (r.pY + r.vY) % 103
		if r.pX < 0 {
			r.pX += 101
		}
		if r.pY < 0 {
			r.pY += 103
		}
		robots[i].pX = r.pX
		robots[i].pY = r.pY
	}
}

func printRobots(day int, robots []Robot) {
	field := createField()
	for _, r := range robots {
		field[r.pY][r.pX] = '#'
	}
	fmt.Printf("\n----\nDay: %d\n----\n", day)
	for _, line := range field {
		fmt.Printf("%s\n", string(line))
	}
}

func createField() [][]rune {
	field := [][]rune{}
	for i := 0; i < 103; i++ {
		line := make([]rune, 101)
		for j := range line {
			line[j] = '.'
		}
		field = append(field, line)
	}
	return field
}