aoc2024/day-09/internal/one/disk.go

package one

import (
	"fmt"
	"slices"
	"strings"
)

type disk struct {
	data      []int
	totalUsed int
}

func newDisk(blocks []block) disk {
	var totalUsed int
	data := []int{}
	for id, block := range blocks {
		for range block.used {
			data = append(data, id)
		}
		for range block.free {
			data = append(data, empty)
		}
		totalUsed += block.used
	}

	return disk{
		data:      data,
		totalUsed: totalUsed,
	}
}

func (d *disk) len() int {
	return d.totalUsed
}

func (d *disk) sort() {
	for i := len(d.data) - 1; i >= 0; i-- {
		if d.data[i] != empty {
			indx := slices.Index(d.data, empty)
			if indx == d.len() {
				break
			}
			d.data[i], d.data[indx] = d.data[indx], d.data[i]
		}
	}
}

func (d *disk) debug() string {
	var sb strings.Builder
	for _, n := range d.data {
		if n == empty {
			sb.WriteRune('.')
		} else {
			sb.WriteString(fmt.Sprintf("%d", n))
		}
	}
	return sb.String()
}