94 lines
1.7 KiB
Go
94 lines
1.7 KiB
Go
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"fmt"
|
||
|
|
"os"
|
||
|
|
"sort"
|
||
|
|
"strconv"
|
||
|
|
"strings"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Given a list of paired integers with columns representing two groups,
|
||
|
|
// compute the total distance between pairs in the sorted lists.
|
||
|
|
func main() {
|
||
|
|
|
||
|
|
// open input file
|
||
|
|
|
||
|
|
input, err := os.ReadFile("input")
|
||
|
|
if err != nil {
|
||
|
|
fmt.Println(err)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Walk the list and create two lists, left and right
|
||
|
|
left, right := extractLists(string(input))
|
||
|
|
|
||
|
|
// Sort left and right
|
||
|
|
sort.Slice(left, func(i, j int) bool {
|
||
|
|
return left[i] < left[j]
|
||
|
|
})
|
||
|
|
sort.Slice(right, func(i, j int) bool {
|
||
|
|
return right[i] < right[j]
|
||
|
|
})
|
||
|
|
|
||
|
|
// lFreqMap := frequencyMap(left)
|
||
|
|
rFreqMap := frequencyMap(right)
|
||
|
|
|
||
|
|
// Walk through left and compare each element to its pair in right
|
||
|
|
|
||
|
|
differenceTotal := 0
|
||
|
|
scoreTotal := 0
|
||
|
|
for idx, val := range left {
|
||
|
|
var l, r int
|
||
|
|
l = val
|
||
|
|
r = right[idx]
|
||
|
|
|
||
|
|
// Sum distance between elements
|
||
|
|
difference := l - r
|
||
|
|
score := l * rFreqMap[l]
|
||
|
|
|
||
|
|
// Take absolute value
|
||
|
|
if difference < 0 {
|
||
|
|
difference = -difference
|
||
|
|
}
|
||
|
|
differenceTotal += difference
|
||
|
|
scoreTotal += score
|
||
|
|
}
|
||
|
|
|
||
|
|
// Return total distance
|
||
|
|
|
||
|
|
fmt.Println(differenceTotal)
|
||
|
|
fmt.Println(scoreTotal)
|
||
|
|
}
|
||
|
|
|
||
|
|
func frequencyMap(slice []int) map[int]int {
|
||
|
|
frequency := make(map[int]int) // val -> score
|
||
|
|
|
||
|
|
for _, val := range slice {
|
||
|
|
frequency[val] = frequency[val] + 1
|
||
|
|
}
|
||
|
|
|
||
|
|
return frequency
|
||
|
|
}
|
||
|
|
|
||
|
|
func extractLists(input string) ([]int, []int) {
|
||
|
|
var left, right []int
|
||
|
|
for _, val := range strings.Split(input, "\n") {
|
||
|
|
// fmt.Println(idx)
|
||
|
|
t := strings.Fields(val)
|
||
|
|
if len(t) < 2 {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
l, err := strconv.Atoi(t[0])
|
||
|
|
if err != nil {
|
||
|
|
panic("aaa")
|
||
|
|
}
|
||
|
|
left = append(left, l)
|
||
|
|
r, err := strconv.Atoi(t[1])
|
||
|
|
if err != nil {
|
||
|
|
panic("bbb")
|
||
|
|
}
|
||
|
|
right = append(right, r)
|
||
|
|
}
|
||
|
|
return left, right
|
||
|
|
}
|