90 lines
1.3 KiB
Go
90 lines
1.3 KiB
Go
package main
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"os"
|
|
"sort"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
func IntAbs(a int) int {
|
|
if a >= 0 {
|
|
return a
|
|
}
|
|
return -a
|
|
}
|
|
|
|
func main() {
|
|
part2(readData("data.txt"))
|
|
}
|
|
|
|
func readData(fileName string) (list1, list2 []int) {
|
|
fp, err := os.Open(fileName)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
scanner := bufio.NewScanner(fp)
|
|
|
|
list1 = make([]int, 0)
|
|
list2 = make([]int, 0)
|
|
|
|
for scanner.Scan() {
|
|
line := strings.TrimSpace(scanner.Text())
|
|
split := strings.Split(line, " ")
|
|
if len(split) != 2 {
|
|
continue
|
|
}
|
|
|
|
value1, err := strconv.Atoi(split[0])
|
|
if err != nil {
|
|
continue
|
|
}
|
|
|
|
value2, err := strconv.Atoi(split[1])
|
|
if err != nil {
|
|
continue
|
|
}
|
|
|
|
list1 = append(list1, value1)
|
|
list2 = append(list2, value2)
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
func part1(list1, list2 []int) {
|
|
sort.Sort(sort.IntSlice(list1))
|
|
sort.Sort(sort.IntSlice(list2))
|
|
|
|
dist := 0
|
|
for i := range list1 {
|
|
dist += IntAbs(list1[i] - list2[i])
|
|
}
|
|
|
|
fmt.Println(dist)
|
|
}
|
|
|
|
func countInstances(list []int) (counts map[int]int) {
|
|
counts = make(map[int]int)
|
|
for _, n := range list {
|
|
counts[n] += 1
|
|
}
|
|
return
|
|
}
|
|
|
|
func part2(list1, list2 []int) {
|
|
counts1 := countInstances(list1)
|
|
counts2 := countInstances(list2)
|
|
|
|
total := 0
|
|
for n, c1 := range counts1 {
|
|
c2, _ := counts2[n]
|
|
total += n * c1 * c2
|
|
}
|
|
|
|
fmt.Println(total)
|
|
}
|