154 lines
3.1 KiB
Go
154 lines
3.1 KiB
Go
package main
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import (
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"bufio"
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"fmt"
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"os"
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"time"
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)
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func main() {
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start := time.Now()
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partOne()
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duration := time.Since(start)
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partTwo()
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duration2 := time.Since(start)
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fmt.Printf("p1: %s, p2: %s\n", duration, duration2-duration)
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}
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var hexMap = map[rune][]uint8{
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'0': {0, 0, 0, 0},
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'1': {0, 0, 0, 1},
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'2': {0, 0, 1, 0},
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'3': {0, 0, 1, 1},
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'4': {0, 1, 0, 0},
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'5': {0, 1, 0, 1},
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'6': {0, 1, 1, 0},
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'7': {0, 1, 1, 1},
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'8': {1, 0, 0, 0},
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'9': {1, 0, 0, 1},
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'A': {1, 0, 1, 0},
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'B': {1, 0, 1, 1},
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'C': {1, 1, 0, 0},
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'D': {1, 1, 0, 1},
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'E': {1, 1, 1, 0},
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'F': {1, 1, 1, 1},
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}
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func makeScanner(test bool) *bufio.Scanner {
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var f *os.File
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if test {
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f, _ = os.Open("inputs/testinput")
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} else {
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f, _ = os.Open("inputs/input")
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}
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reader := bufio.NewReader(f)
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return bufio.NewScanner(reader)
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}
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func parseNumber(stream []uint8, length int) int64 {
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result := int64(0)
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for i := 0; i < length; i++ {
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result += int64(stream[i]) << (length - 1 - i)
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}
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return result
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}
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type packet struct {
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version int64
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typeID int64
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subPackets []packet
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encodedNumber int64
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}
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func getPacketVersion(stream []uint8) int64 {
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return parseNumber(stream, 3)
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}
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func getPacketType(stream []uint8) int64 {
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return parseNumber(stream, 3)
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}
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func getSubpacketLength(t uint8, stream []uint8) (int, int64) {
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if t == 0 {
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return 15, parseNumber(stream, 15)
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}
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if t == 1 {
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return 11, parseNumber(stream, 11)
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}
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return 0, 0
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}
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func parsePayload(stream []uint8) (int64, int) {
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num := []uint8{}
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pos := 0
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chars := 0
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for {
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currentsegment := stream[pos : pos+5]
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chars += 4
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num = append(num, currentsegment[1:5]...)
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pos += 5
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if currentsegment[0] == 0 {
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break
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}
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}
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return parseNumber(num, chars), pos
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}
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func parsePackets(stream []uint8) (int, packet) {
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if len(stream) <= 7 {
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return 0, packet{}
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}
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parsedPacket := packet{}
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parsedPacket.version = getPacketVersion(stream[0:3])
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parsedPacket.typeID = getPacketType(stream[3:6])
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if parsedPacket.typeID == 4 {
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encoded, consumed := parsePayload(stream[6:])
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parsedPacket.encodedNumber = encoded
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return consumed + 6, parsedPacket // 6 is packet header length
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} else {
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parsed := 0
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size, subpacketlength := getSubpacketLength(stream[6], stream[7:])
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for {
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consumed, subs := parsePackets(stream[7+size+parsed:])
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parsedPacket.subPackets = append(parsedPacket.subPackets, subs)
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parsed += consumed
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if size == 11 && int64(len(parsedPacket.subPackets)) == subpacketlength {
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return parsed + 7 + size, parsedPacket
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} else if size == 15 && int64(parsed) > subpacketlength || consumed == 0 {
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return parsed + 7 + size, parsedPacket
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}
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}
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}
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}
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func countVersions(pac packet) int {
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i := int(pac.version)
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for _, p := range pac.subPackets {
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i += countVersions(p)
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}
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return i
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}
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func partOne() {
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scanner := makeScanner(false)
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scanner.Scan()
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line := scanner.Text()
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stream := []uint8{}
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for _, hex := range line {
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stream = append(stream, hexMap[hex]...)
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}
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_, parsedPacket := parsePackets(stream)
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fmt.Println(countVersions(parsedPacket))
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}
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func partTwo() {
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scanner := makeScanner(false)
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for scanner.Scan() {
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// line := scanner.Text()
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}
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}
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