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