adventofcode/2024/01/main.go

package main

import (
	"fmt"
	"sort"

	"aoc/helper"
)

type list struct {
	left  []int
	right []int
}

func main() {
	list_a, list_b := helper.ReadLinesTwoIntSlices()
	list := list{left: list_a, right: list_b}

	// part 1
	distance := list.distance()
	fmt.Printf("Distance: %v\n", distance)

	// part 2
	similarity := list.similarity()
	fmt.Printf("Similarity: %v\n", similarity)
}

func (l list) distance() (dist int) {
	sort.Ints(l.left)
	sort.Ints(l.right)

	for i := range l.left {
		dist += helper.Abs(l.left[i] - l.right[i])
	}

	return dist
}

func (l list) similarity() (sim int) {
	for _, lval := range l.left {
		valcount := countIntInSlice(l.right, lval)
		sim += lval * valcount
	}

	return sim
}

func countIntInSlice(lst []int, i int) (count int) {
	for _, val := range lst {
		if val == i {
			count++
		}
	}

	return count
}