108 lines
2.5 KiB
Go
108 lines
2.5 KiB
Go
package main
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import (
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"crypto"
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_ "crypto/sha1"
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"encoding/hex"
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"fmt"
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"math/rand"
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"time"
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)
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func main() {
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g := Generator{
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Difficulty: 26,
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}
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c := g.RandomChallenge()
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fmt.Println(c.String())
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fmt.Println(c.Solve().String())
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}
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type Challenge struct {
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Input [48]byte
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Date [20]byte
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Difficulty byte
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Solution int64
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}
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type Generator struct {
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Difficulty byte
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}
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func (g *Generator) RandomChallenge() Challenge {
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bytes := make([]byte, 48)
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for i, _ := range bytes {
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bytes[i] = byte(rand.Int())
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}
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today := time.Now().UTC()
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date := today.Format("2006-01-02")
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hash := crypto.SHA1.New().Sum([]byte(date))
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return Challenge{
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Input: [48]byte(bytes),
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Date: [20]byte(hash),
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Difficulty: g.Difficulty,
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}
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}
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// using a lookup table for this is super goofy but i'm lazy and it's 6am
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var prefixLookup = []int{
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8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
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3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
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2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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}
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func (c Challenge) Solve() Challenge {
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bytes := make([]byte, 76)
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bytes = append(bytes, c.Input[:]...)
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bytes = append(bytes, c.Date[:]...)
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for {
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for i := range 8 {
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bytes[75-i] = byte(c.Solution >> (i * 8))
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}
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sum := make([]byte, 20)
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hash := crypto.SHA1.New()
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hash.Write(bytes)
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sum = hash.Sum(nil)
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count := 0
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for _, c := range sum {
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p := prefixLookup[c]
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count += p
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if p != 8 {
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break
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}
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}
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if c.Solution%20000000 == 0 {
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println(c.Solution)
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}
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if count >= int(c.Difficulty) {
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println(c.Solution)
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break
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}
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c.Solution++
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}
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return c
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}
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func (c Challenge) String() string {
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bytes := make([]byte, 0)
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bytes = append(bytes, c.Input[:]...)
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bytes = append(bytes, c.Date[:]...)
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bytes = append(bytes, make([]byte, 8)...)
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bytes[68] = c.Difficulty
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for i := range 7 {
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bytes[75-i] = byte(c.Solution >> (i * 8))
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}
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return hex.EncodeToString(bytes)
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}
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