99 lines
1.6 KiB
Go
99 lines
1.6 KiB
Go
package main
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"log"
|
|
"os"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
var list []int
|
|
var skip, idx, length int
|
|
|
|
func main() {
|
|
part := 2
|
|
if len(os.Args) > 1 {
|
|
if os.Args[1] == "-1" {
|
|
part = 1
|
|
}
|
|
}
|
|
length = 256
|
|
for i := 0; i < length; i++ {
|
|
list = append(list, i)
|
|
}
|
|
|
|
inp := StdinToString()
|
|
if part == 1 {
|
|
part1(inp)
|
|
} else {
|
|
part2(inp)
|
|
}
|
|
}
|
|
|
|
func part1(inp string) {
|
|
fmt.Println("= Part 1 =")
|
|
lngths := strings.Split(inp, ",")
|
|
for i := range lngths {
|
|
round(Atoi(lngths[i]))
|
|
}
|
|
fmt.Println("Result:", list[0]*list[1])
|
|
}
|
|
|
|
func round(i int) {
|
|
// if idx+i overflows, pull from the front
|
|
var revList []int
|
|
for j := idx; j < idx+i; j++ {
|
|
revList = append([]int{list[j%length]}, revList...)
|
|
}
|
|
for j := 0; j < len(revList); j++ {
|
|
list[(idx+j)%length] = revList[j]
|
|
}
|
|
|
|
idx += i + skip
|
|
skip++
|
|
}
|
|
|
|
func part2(inp string) {
|
|
inpBts := []byte(inp)
|
|
inpBts = append(inpBts, []byte{17, 31, 73, 47, 23}...)
|
|
for j := 0; j < 64; j++ {
|
|
for i := range inpBts {
|
|
round(int(inpBts[i]))
|
|
}
|
|
}
|
|
// Now calculate the dense hash
|
|
var dense []byte
|
|
for i := 0; i < len(list); i += 16 {
|
|
dense = append(dense, xorList(list[i:i+16]))
|
|
}
|
|
fmt.Printf("%x\n", dense)
|
|
}
|
|
|
|
func xorList(inp []int) byte {
|
|
var ret byte
|
|
for i := range inp {
|
|
ret ^= byte(inp[i])
|
|
}
|
|
return ret
|
|
}
|
|
|
|
func StdinToString() string {
|
|
var input string
|
|
scanner := bufio.NewScanner(os.Stdin)
|
|
for scanner.Scan() {
|
|
input = scanner.Text()
|
|
}
|
|
return input
|
|
}
|
|
|
|
func Atoi(i string) int {
|
|
var ret int
|
|
var err error
|
|
if ret, err = strconv.Atoi(i); err != nil {
|
|
log.Fatal("Invalid Atoi")
|
|
}
|
|
return ret
|
|
}
|